problem I see with Android is yes they all have better specs currently but really if WP7 was running on those specs the phone would be a monster. It would be like having a xbox 360 phone. Games would be insane, os would have no chance of any lag. With Android you get more lag, horrible battery life, apps that don't work smoothly with any android device you pic up and I'm sorry but the Android games vs WP7 games is a joke. Yeah you got the specs to help out but the games still suck. I have owned 5 different Android device's and none of them run as smooth as my Trophy does. And yes I used custom roms and still not close. I probably went through 15-20 different roms. Yes they sped up but not after a bit was back to normal. Plus its really a pain in the butt to have to check for new roms when I can just carry around my Trophy and never have to worry about it.
Battery life is subjectiv depending on which phones you're talking about and how you use them. I have both a Sensation and HD7 and battery life on my Sensation blows the HD7 out of the water. I can browse the web, use Facebook, play games, listen to music, and watch YouTube without having to worry about battery life draining fast. With the same use on my HD7, it cant even last a day. Not only that but I have widgets running on most of my screens and am multitasking. WP7 can't even multitask with 3rd party apps yet and battery life is already abysmal.
WP7 lags here and there. I've had my HD7's homescreen lag from time to time. It usually occurs when I'm navigating while a webpage is loading in the browser. Stock for stock, the WP7 UI is a little smoother but with a custom launcher installed on my Sensation (ex. Launcher Pro), it runs just as smooth, or even smoother than my HD7.
You say android apps don't run smooth but I've yet to run into an android app that isn't smooth. On WP7, I've run across quite a few apps that didn't run as smoothly as their android counterparts. The official Facebook app on WP7 is down right terrible. It's laggy, slow and doesn't offer the kind of functionality as the Android and iOS versions. The same can be said for the official YouTube app on WP7. Laggy scrolling and limited functionality. I've also yet to see a WP7 phone that can do video playback as smooth as my Sensation.
Games have been better on Android in my experience. An example like I posted in another thread today is Angry Birds. I have the game on both my phones. On the HD7, it plays pretty smoothly but on my Sensation it plays a lot smoother. Could be the superior hardware of the Sensation, who knows... I've played a racing game on each and again, the Sensation played it smoother. I think the only reason some ppl might praise gaming on WP7 is due to the Xbox live titles. In my own experience, Android handled gaming a little better but of course you don't get the whole xbox intergration like you do on WP7.
Don't get me wrong because I like WP7. I've been enjoying my HD7 for months but I tell it like it is. Android is a heavier (more feature packed) OS at the moment while WP7 is lighter, although it will get heavier with Mango. You can't go wrong with either OS.