I gave my iPhone 4 to my wife and got the Samsung Focus - I think it’s a much better phone and I haven’t had any trouble with it, even after adding an “uncertified” 32GB microSD card, to give it 40GB.
I also love the fact that I was able to un-install iTunes from my computer - I HATE that program. Don’t tell me there aren’t any apps, either. I’ve got the Kindle app, as well as two other free ebook readers, both linked to my Calibre ebook server on my Windows Home Server, which I also have an app for on my phone. Not to mention the games linked to my XBox Live.
I also like streaming my Netflix to the phone, as well as downloading movies from my home server to the phone. This phone is great, and about to get even better.
The MS tech may be comparable, but MS is viewed as yesterday’s news by the youth (who are coveted by all marketing and ad companies). IPAD/IPHONE and DROID have left MS in the dust as far as the “cool” factor. This is very problematic for MS, as they can not brute force these two competitors out of the market.