The top of the line Android phones are great, powerful devices which are very capable in some ways no smartphone has ever been before. They are a great choice for people who enjoy tinkering and like getting lost in the phone....but
My opinion is that the vast majority middle of the road and low-end Android devices are atrocious and nearly every average user would be better served by almost anything else. A Blackberry, an iPhone 3GS. A really good feature phone. At least those devices don't fail at basic dependability and being reliable communications devices and meeting their primary purpose just to pack in bogus bells and whistles and bloatware.
My opinion is that mid-pack and cheap Android devices are just pure crap, unreliable, cluttered junk. I think it says something about Google's integrity that they not only had a shill sit on Apple's board and poach their ideas, but then took virtually no responsibility for the end user experience and what Android turned into.
Android's popularity has far more to do with filling a huge void left by Apple's refusal to give iOS away to anyone who wanted it or compromise to make cheap phones than it does with it being a good product.
I will say that ICS is the first version of Android I've seen that actually looks like Google gave a crap about what the finished product looked like. It's pretty slick. But the broken Android model means almost every phone on sale now still comes with Gingerbread and the upgrade path is completely random and uncertain.
I think it serves a purpose, but I firmly believe that at least 80% of the people who get Android phones wind up with them because it's almost impossible to go to a phone store and NOT get an Android, or because an Android fan boy friend goaded them into it, or some misplaced resentment towards the popularity of the iPhone.
Maybe 20% are actually informed consumers or enthusiasts.
I know maybe 3-4 people who have Android phones and like them. Every other person I know dislikes their Android but is stuck with it for one reason or another, or has gotten rid of their Android for an iPhone because they got fed up with the directionless cat herding cluster*ck.
Your mileage may vary.
Windows Phone is way more limited than Android. No one would deny that. Sometimes more of everything doesn't always result in the best final product. That applies to lots of things, art, music, cuisine, literature, and yes, IMO, smartphones.