Couple of thoughts about using Windows Phone 8 for two days..
It's definately smooth, most of the time, what i mean is some apps like Twitter and Whatsapp launch faster on Android (ancient HTC Wildfire), if you switch to them via multitask window, it's instant, but if you launch it from the live/tile it takes 2, 3 seconds, even if you didn't back out of it with back button, so it should be in the memory, but it's not instant..
This is only the case for a few apps..
Keyboard is absolutely fantastic, such a joy to type..
There is no easy toggle for silent mode, just ringtone+vibrate and vibrate, if you want it completely silent you have to go settings then turn off ringtone and vibration seperately.
There's no proper Gtalk client so far (haven't tried them all), all works fine when the phone is on, but in standby they dont' give you push notifications.
Browsing is a pain, at least on my phone with 512ram, maybe it's better on 1gig models. It's nowhere near the speeds of Opera Mini which was my default browser on Android, pressing back in IE reloads the damn page again, it doesn't even refreshes it, just reloads it for an anooying few seconds of white screen, and there's no forward also..
Other most popular browser on the store just keeps crashin, so something like Opera Mini is definately needed.
What else, yes the battery percentage apps are not completely realtime, meaning if it shows 10% it's most likely 7%, you can see that when you open the app.
Another annoyance is that there's no separate volume controls, if you turn down the media clip, it also turns down the ringtone and alarm level.. pretty stupid.
So that's a few things i've noticed so far, maybe it will use someone..