I feel obligated to speak on this matter.
I am a user of all mobile OS. My wife has an iphone and ipad. i have used an ipod touch for almost a year before getting a WP7 handset. i also have a tablet, HP Touchpad with CM9 installed. I am a frequent user of WebOS and ICS android.
The obvious comparatives
Apps - not as many, but still a good selection. do i with there were more; yes and no. for my frequent usage of twitter, facebook email for gmail and hotmail i am set. the integration of twitter and facebook into the phone without the need for apps if tremendous. on android, webos, and my ipod (2nd gen, so not able ot use iOS5) i spend/spent about 10 - 15 mins in each app checking statuses, posting my updates, reading pages, etc... with WP7, i used the people tile, look at them both at the same time, i am done in half the time and on my way. I can post to both twitter and facebook at the same time, no need to type the same message twice (great for people who like to post on both) i also have the option to only post to one from the same tile.
email is the same. both accounts are in the same tile, i see both, i can email for either account by simple selecting when i compose a new message.
for those that use IM, facebook message, etc... i can do all that on my phone without opening the app. i go to my messaging tile, and type to whom ever. if they send me a message via facebook, but go offline, i can easily keep the same conversation open and choose to txt them immediately.
OS - it is beautiful. plain and simple. it is smooth, plain and simple. the best part is the live tiles. the weather channel for instance. it is one of the first set of icons i see when i unlock. within 20 seconds i would say, i know what the weather is (temp, conditions) then i close my phone. no need to go into the app and see. it also shows me a radar at the same time (be it 20 or so seconds later once the tile live updates again)
its not perfect, dont get me wrong, but none of the OS's were early in their life.
i respect some people when they say the OS released this last (compared to when other OS's were released) it should have all the same features as the current platforms, and then some. which i agree, i also disagree. most notably is copy/paste. it should have been there day one, but it did not take away from the OS in all honestly. it is very versatile and is enjoyable if i was limited to one word.
again, i am not some fan boy who only uses WP7 and no other OS. i use my table daily for everything.
movies, web surfing, gaming, facebook, twitter, etc... one would say i use my tablet (again, HP touchpad with WebOS and Android ICS) more than my phone. but i would give up both those OS's if i could installed WP7/WP8 on this tablet. and i love my WebOS and Android.
I can truely say though, iOS is boring to me after using the other 3. i like to multitasking of WebOS and ICS, i love the customization and controlabiltiy of WebOS and ICS, but WP7 is just simple, smooth and to the point and that makes it my choice.