Amare is playing much, much better than Bosh, although both got off to slower starts and have picked it up.
Again, you have to look at the situation. Amare has a usage rate of 30+, while Bosh is only around 23.
Amare is playing with a guy in Felton who is playing like a top 5 PG, but even though he is their 2nd best player, he only has a usage rate of 22. They play at an extremely high pace compared to MIA who is one of the slowest teams in the league.
Bosh plays with two players who's usage rates are up above 30. Amare has no one even close to that, as the 2nd best player on his team is far below that.
Yes, in theory, playing with Wade/Lebron should be easier, but if you look at how things have played out and what that team is, it is a lot of ignoring the post, a lot of grinding things out and focus on defense.
There is a reason why MIA is the best defensive team in the league and why they play at a snails pace.
NY doesn't play defense. They are 18th in defensive efficiency while MIA is #1. Even though NY plays at 3rd fastest pace, they are still behind MIA in offensive efficiency (meaning when normalizing the numbers, MIA is the better offensive team).
So don't act like Amare has definitively proven anything yet. Use your brain and evaluate the situation. Amare is playing better but my point remains, whomever you believe is better, the difference is probably not that great. If things keep going they way they are, Amare will definitely but enough gap between the two to say he is definitively better, but from everything we have seen for their careers, it could be argued either way.