What is the difference in setting up a device at obitalk.com and setting one up through the device interface(http://xxx.xxx.xxx.xx)?
Thanks
Mostly personal preference.
There is nothing you can do on the Dashboard or Expert which cannot be done on the device if you have access to it. That is not always the case, eg remote location.
Once properly configured by either method there is no difference in call quality.
I set up SP2 on the device, but I don't see it on the dashboard. Is there an option that allows you to see it on both?
No. See http://www.obitalk.com/forum/index.php?topic=92.0
Making all changes from the OBiTalk server is easier for most people. But you cannot mix them. You can set things up on OBiTalk and view via the local web interface. That is the only way to see the call logs. You could make temporary experimental changes. But if you later use the OBiTalk server, those changes could be overwritten.