I have a different opinion than the previous poster. Although I respect his opinion. Everyone has their own needs, likes, and dislikes re: a Smartphone Platform.
I had an iPhone 4s for a while. I dumped my BlackBerry to try it out. I also have used an Android for a year as my backup phone because I needed it for depositing checks, and for signing up for things like Instagram that you can only do via a mobile device and not online. For a while I liked Droid, and their Google integration. I use Google calendar a lot to schedule my business life. It transfers to all my phones seamlessly as do my Google contacts. Yes, even to my WindowsPhone 8. No problem. You just need to set-up your Gmail account on your WP8 and link Google to the people HUB and voila, all your contacts and appointments are synced easy peasy.
I liked my iPhone 4s. It sure has lots of apps if that's your gig. Not me. I use probably 10 apps on a regular basis. The rest are not important to me. But if you hear of an app in the marketplace, yep, you can get it on iPhone. I didn't like the way iPhone apps must dump onto your home screens, unlike Droid where you can download them and YOU decide to place them on the screen or not. Yes, you can folder iPhone apps, but they are always present somewhere on one of your screens. Not so with Droid. I also did not like the one button control on iPhone with the rest being pushed to the apps. I preferred the BACK, HOME, SEARCH buttons on Droid. After a few months of goofing around with Siri (she was useless in my opinion. "Sorry, I can't understand "Find me a Coffee House", do you want me to search the web for that?") I gave my iPhone to a dear friend and said "goombye" to Apple. It's not for me. I Went back to BlackBerry for BUSINESS and decided to use my Droid for fun, music, play, banking, directions, etc.
Then I got a WindowsPhone Nokia 521. How could I resist? Under 100 bucks with accessories?
I love it. I think that the OS and UI are smooth, intuitive and "fun" to use. The live tiles are great. Like Droid, apps are in the background, and you can PIN them to the home screen. SOME are "live" so you get live tiles. Even it it is an accounting of app indications like "5 messages and 2 invitations in LinkedIn". As I said, I have no issues with Google. Gmail is fine. You can app it, or create a Google email account and merge or not merge it with other email accounts. If you have contacts and appointments in Google Contacts and Calendar, they download and merge. I like Nokia Music and Xbox Music. Prefer Nokia, and like the live free mix streaming. Nokia apps are pretty cool. I wish I could use "City Lens", but the 521 does not support it. You must have "Compass" ability.
Net, net, after using WindowsPhone8 for 3 or so weeks, I find my Droid clunky by comparison. I still reach for my BlackBerry for business, but probably because I have used Berry for so long it is 2nd nature to me to crank out email, text, and LinkedIn/Facebook/FourSquare on it. However, the Business HUB on a WindowsPhone8 is not to be sneezed at. MS integrates MS Office very well. And as mentioned above in other posts, the People Hub is amazing. All your social feeds funnel there so seamlessly. I also like the "me" page. It is a convenient hub to see what's up with your connections.
Cranking out emails and texts is good. One thing about iOS, they have a great UI for typing. MS has done a great job too. Stock Droid is not great as far as I have found, so I had to buy SwiftKey to like my typing experience on Droid. Not so on Windows. The typing is fluid, and if you want to dictate your emails or texts, the Voice Recognition is good.
So, I could just have my WindowsPhone8 and be happy. For me, it is the answer for a great business phone and a nice personal digital assistant and entertainment device.
That's my 2 1/2 cents worth. YOU have to decide what to do. For me, it's a slam dunk. I'd choose a "NOKIA" WindowsPhone8.
Good luck. Enjoy.