I switched from an S3(Virgin Mobile) to the Desire 816. It's been about a month. I like the bigger phone, it helps as I have big fingers. The S3 was and is a great phone however I had so much junk I needed to turn off just to get a decent battery life. I am not on FB or Twitter, still, a lot of things to turn off. With the 816 I feel there is far less bloatware. At least I can't find it the applications to turn off. The list is a lot shorter.
Also, 816 takes a lot more time to set up the way I want than the S3. That could be because I was with Samsung for so long or it could be that with the S3 there are several ways to turn one function on and off and with the 816, just one clear path. I love my 816. Feels solid in my hands, batter last longer, fewer freeze up(while using less ram) and when taking pictures my fingers never block the lens.
Cons: Slow Camera and screen brightness