the first and one of the most important reasons I choose android is because Apple is like the Nazis. They have a very tight death grip on everything they make. They can pull apps from the market just because they simply dont like them, and no hardware can be added to the phone without apples say so (someone tryed to make a case w/flash for the 3g).
second. apple dose have more apps, but apple has also been out for a few years before android. and like said earlier most are now being ported to android and more good devs are starting to program for this phone.
and lastly. If you look at the wave of when android started to now they went from one phone on tmobile to around 3 or more phones per phone company. so that means that any apps you buy can transfer to a different phone and you aren't stuck to just one provider. If things keep going the way the are android will rule the market.