I recommend NOT buying a Samsung smartphone!!! I went through a lot of trouble with my Samsung smartphone, and just recently was able to upgrade it to an iphone4.
Many features of my Samsung Epix did not work. The GPS was the biggest problem, and is well known across the internet. Other problems- voice dialing didn't work, and the phone was extremely slow when browsing the 3G network. There was no support from Samsung for these issues, they just went onto other phones like the Jack and so forth. My phone came with WM6.1. Microsoft released WM6.5 a long time ago, but Samsung did not make it available for the Epix until a full 2 years after the phone came out.