The best bible translation is really the one that you can pick up and understand easily. The Bible is meant to be understood, and if you do not understand a particular translation then it isn't helpful.
There are many who claim that a certain translation of the Bible is the only authoritative translation, but when you examine bible verses across multiple translations you will find that the meaning stays the same.
Very rarely do translations differ enough that a verse can have different meanings, and even in these rare situations the difference is not significant enough to change the foundational beliefs of Christianity.
Essentially, all mainstream translations of the Bible are candidates for being the best bible translation for you. The only exception would be something like "The Message" which is not a translation but a paraphrase of the Bible. Otherwise, it just depends on how easily you understand the language of that particular translation.
All languages change significantly over time, including English. Just pick up a 1611 King James Bible and see how different English used to be 400 years ago. Certainly you can try to familiarize yourself with that older version of English, but for most people it is easier to be able to just pick up a Bible and understand it without much effort.
Part of the issue with those who argue for a best bible translation is that they "miss the forest for the trees." They are so focused on the small details of particular verses, that they miss the overall message of the Bible.
Rather than arguing about what particular verses mean, they should be teaching what the overall message is.
The books of the Bible originally did not have chapter numbers or verse numbers. They were simply regular books and letters, and they were meant to be read as such. For example, the "letter" to the Romans is meant to be read in one sitting, not verse by verse or even chapter by chapter. A lot of incorrect theology comes from reading Romans in pieces. There are Christians who use certain verses in Romans in order to support beliefs that Paul himself opposes in the exact same letter.
These believers are also missing the forest for the trees. They want to argue by saying "but this verse says" while neglecting what the message of the overall letter.
As an example of missing the forest for the trees, in Romans, Paul says, "that if you will confess with your mouth the Lord Jesus, and believe in your heart that God raised him from the dead, you will be saved. For with the heart, one believes unto righteousness; and with the mouth confession is made unto salvation." (Romans 10:9-10 WEB)
These two verses are used to support the concept of "saved by grace," which is true in part. However, typically those who teach about salvation using Romans 10:9-10 neglect the role of repentance and obedience to God. These believers, in oppositions to the concept of "saved by works/obedience," swing to the opposite side of the spectrum of "saved by grace – works don't matter."
However, in Romans 10:9-10, Paul is not making a summarizing statement of salvation. This is the very end of Paul's letter, and he has been discussing repentance and salvation through most of it.
Up until this point, Paul has made these comments:
"Do you know this, O man who judges those who practice such things, and do the same, that you will escape the judgment of God? Or do you despise the riches of his goodness, forbearance, and patience, not knowing that the goodness of God leads you to repentance?" (Romans 2:3-4 WEB)
"[God] who 'will render to every man according to his works:'...but to those who are self-seeking, and don't obey the truth, but obey unrighteousness, will be wrath and indignation..." (Romans 2:6,8 WEB)
"Do we then make the law of no effect through faith? May it never be! No, we establish the law." (Romans 3:31 WEB)
"What will we say then? Shall we continue in sin, that grace may abound? May it never be! We who died to sin, how could we live in it any longer?" (Romans 6:1-2 WEB)
"Therefore don't let sin reign in your mortal body, that you should obey it in its lusts. Neither present your members to sin as instruments of unrighteousness, but present yourselves to God, as alive from the dead, and your members as instruments of righteousness to God." (Romans 6:12-13 WEB)
"Don't you know that to whom you present yourselves as servants to obedience, his servants you are whom you obey; whether of sin to death, or of obedience to righteousness?" (Romans 6:16 WEB)
Paul is not writing to be cryptic or secretive. He is writing to be understood. Obedience is necessary for salvation, and he is not talking about "believing in Christ" as being obedience. The Roman Christians who Paul is writing to were already believers. Their problem wasn't belief, it was sin. He is talking about obedience as in "repentance as seen by no longer sinning."
In other letters, Paul also makes statements like:
"Circumcision is nothing, and uncircumcision is nothing; but obeying the commandments of God is everything." (1 Corinthians 7:19 NRSV)
"They profess that they know God, but by their works they deny him..." (Titus 1:16 WEB)
So if Paul says all of this in Romans, why doesn't he mention it as part of Romans 10:9-10? It is because he has already spent the first half of his letter making it clear about the relationship between faith and obedience and salvation, and having said all that to his audience, he clearly does not feel the need to restate it.
He has already discussed the subject in chapter 2, 3, 6, and 8 – and the chapters in-between are various elaborations on why repentance and avoidance of sin is necessary for salvation.
Paul's entire argument in Romans 2 is that obedience is what makes a Jew a Jew (God's people), not physical circumcision (Romans 2:29).
Now, in Romans 10, the focus of this portion of his letter is on the fact that salvation is for everyone (who repents). He is done making his point about faith and obedience and salvation. He has already clarified and re-clarified and re-emphasized that point over the course of several chapters; he now focuses on a new point.
This is how people "miss the forest for the trees."
The message of the Bible is definitely important, but we must be careful not to miss the forest for the trees by being so consumed with particular verses that we miss the overall message.
Rarely is the message of a "passage," and absolutely never is the message of an entire letter, hindered by the particular words used in a particular verse. In context, there is no confusion what the author means. The confusion comes from taking verses out-of-context and examining them by themselves by trying to discover the true meaning of one sentence.
They miss the point.
Note: There can be value in studying individual verses, but not to the extent that we lose sight of the overall message. The context should always come first.
The main differences in bible translations is whether it was translated more word-for-word or thought-for-thought. All languages have idioms, which are phrases that have an implied meaning that is different from the literal meaning.
For example, in English, if someone says they "let the cat out of the bag" most English-speakers understand that there is not a literal cat being let out of a bag. Instead, this idiom means they "told the secret." Or in England, if someone says they traveled "across the pond," it is understood that there is not a literal pond. Instead, they are saying they traveled "across the Atlantic Ocean" which is quite a bit larger than a pond!
Idioms are cultural, so by translating the Bible word-for-word, there can be phrases that do not make sense to most people. For this reasons, many translations may translate more thought-for-thought in order to communicate the message effectively.
Word-for-word translations will translate a verse literally as "let the cat out of the bag" while thought-for-thought translations will translate "tell the secret." Really, no translate is completely word-for-word or thought-for-thought. Rather, all translations range on a spectrum between the two extremes.
An example is in Numbers 15:30.
A more "word-for-word" translation is, "But the soul who does anything with a high hand, whether he be home-born or a sojourner, the same blasphemes Yahweh; and that soul shall be cut off from among his people." (WEB)
Is this verse confusing?
Let's consider a more "thought-for-thought" translation: "But anyone who sins defiantly, whether native-born or foreigner, blasphemes the LORD and must be cut off from the people of Israel." (NIV)
Now does this verse make sense?
Thought-for-thought translations have taken the time to figure out what these idioms meant, so that you can understand it without hindrance.
A great English Bible translation is the New Revised Standard Version, but many other English translations are equally great. As long as you can easily understand it, then it serves it's purpose, because the entire purpose of translating the Bible into a language is that those who speak that language can understand it.
"You ought to live holy and godly lives as you look forward to the day of God..." (2 Peter 3:11-12 NIV)
"Make every effort to be found spotless, blameless and at peace with him." (2 Peter 3:14 NIV)