Abel:
I disagree that live tiles are better. They're good, but hard to say they're a better system than the android homescreen system.
User friendly... Well maybe. Its easier and cleaner. I think several things in wp is more troublesome than in android. For instance toggles, and settings. Finding the equalizer, for instance, is insanely annoying in wp.
The fluidity of WP is great. The delays are covered with animations and it seems to flow well, at least consistently.
Generally the apps in wp have a more uniform look, albeit less customizable.
Proshot i have no experience with.
Amazing Weather HD isn't any better than some of the android alternatives.
Email integration is about equal, except you can send more filetypes on android.
Office editors are available for Android, though it is great on WP8.
Gamingwise it's worse on wp, obviously.
Kinslayer: My WP blasts notification sounds over my music in wp. It doesn't mute the sound though, as you say it does on android. Not sure if that happens on my s4, I haven't noticed it at least. I'll try to pay attention to it next time, but I haven't noticed it being intrusive at all.
Android isn't always as fluid as WP, but most of that is due to WP masking very well with animations.. With regards to occasional lag it happens less frequently in WP for sure. My s4 had some lag when pressing the homekey to return to the homescreen from for instance Internet. I discovered that the perceived lag was merely an animation delay, which (since its android) I could remove, making it snappier..
As for the nexus vs Samsung thing, I think it's mostly due to the version/phone you were using. On s4 the Samsung overlay is quite well done.
Ridemyscooter: today you can make your android look basically however you want it to look. So however futuristic you might feel wp is, android can do it as well. If desired.. Clunky is definitely not a good description.
Android phones are as cluttered and mismatched as the user wants. The cleanest sleekest coolest homescreens are on android. The worst are as well.
The fact is that widgets on android allows you to make it what ever you want.
I recently switched from 920 to s4.
My experience so far is this:
Spotify works flawlessly now.
Battery is greatly improved.
Video playback is far better.
The personalization is great.
FB chat is amazing. I like flicking the heads around the homescreen.
Design wise I prefer the s4.
Stutters at random. Not often but sometimes.
Configuring your homescreen PEERFECTLY is a huge daunting task that can be overwhelming. But I love that I can.
It charges insanely fast, which is good.
Split view is great.
Air view is actually useful. Same goes for air gestures, but not as much as air view.
Eye control works well, but not something I use.
SwiftKey is far better than the wp8 keyboard.
All in all its a big change, but one I'm happy about so far.