There will be people that will always say that Bosh is better than Amar'e because of his age and durability, the fact that he never had microfracture surgery and the fact that Lebron and Wade wanted him over Amar'e.
Amar'e had microfracture surgery but since then has been extremely healthy. He doesn't miss many games at all.
On the contrary Bosh may not have had microfracture surgery but what may arguably be worse is that he misses about an average of 10 games per season.
Stoudemire on the other hand missed a ton of games due to microfracture surgery, a ton of games due to the eye injury which was a freak injury, but other than that in every season he's been fully healthy (except one) he's played nearly every game (in 07-08 he missed 3 games, which is typical for an NBA player).
If anything Bosh's recurring nagging injuries are the type that are going to turn into major injuries in the long run, whereas Amar'e got hurt and is very clearly over it at this point.
Also there's barely an age difference, it's maybe a year and four months which is not much at all.
And LeBron + Wade did not want Bosh over Amar'e...they were good with either one...it's just that Wade (and eventually LeBron) had no interest in going to NY, whereas Amar'e basically jumped at the chance to come and anchor this Knicks team. It's not that LeBron + Wade didn't want to play with Amar'e, it's more that Amar'e chose to rise to the challenge of playing in New York whereas LeBron on the other hand was a pussy and instead went somewhere where he would be able to stay out of the spotlight (lot of good that did, he became the most hated man in American professional sports in a matter of minutes).