Summary: My previous phone was a Lumia 710 and I was really excited to jump to Windows Phone 8 and use the the 810. I do like this phone but let me first mention what let me down. Spec wise I really wished the 810 had 16 GB of internal storage (like the 822) as the OS takes up a lot and you're only left with 4 to 5 GB available out of the box.
Pros: Exclusive Lumia apps, solid construction
Cons: Only 8 GB internal storage, microSD card issues, limited support by T-Mobile.