There is a reason i quickly asked for an i760 back. The keypad on the front was/is essential. The speed at which the i760 and 6800 changes from portrait to landscape is about equal... The micro sd card size limit on the 6800 is good and the wifi was equal. The way you change from airplane/vibrate/wifi/ etc was nicer on the 6800 as was the scroll wheel. The sliding keyboard is opposite on each phone. The i760 feels way sturdier as does the sliding function. The speaker on the 6800 sucked!
When i received my 6800 i was instructed to send back in my i760 w/in 10 days as was the case when i received my i760 back. There was no plan changes just phone swaps.
Not a whole lot of improvement from 6.0 to 6.1. I have had it running w/o turning it off for a week and no problems. I am not running any 3rd party aps yet on 6.1. There are a few minor things but not enough to risk bricking it.