I like my 8820 because i use gps and wifi.

my 8310 only had gps

i have no need for a camera so it was a quick decision for me since the wifi will be good go have in my home as i do not get good reception inside. my service provider has a feature that allows me to make calls over a wifi network. that is why i chose the 8820.

i've had an 8800 before, so going back to it was not a problem. i do not like one or the other better, they're equally the same to me except that i find the 83xx series a little more attractive looking. that's it.