If you go on BB web site and compare the 2 I think the 8820 is better, it also depends on who your SP is: 8830 cdma and 8820 gsm that is the biggest difference.
If you settle on the 8830, after considering what features you need, then give the same consideration to your choice of carrier, since you appear to have a choice. Read the forums and see if any of the issues that get discussed pertain to you. For example, Sprint doesn't provide MMS. That may not matter much if you get the 8830, since it doesn't have a camera. Verizon disables the GPS in their phones.
Do your homework up front and you'll reduce the chance of unpleasant surprises.
Posted from my CrackBerry at wapforums.crackberry.com
