I just picked up my 2011 Edge on Friday which already had Gen 2 installed by default. After reading all the issues on this forum for the last few months I am very impressed with sync and have no real issues with any of the features (though I haven't used everything extensively yet).
Responsiveness is a non-issue... it's no iPhone.. but completely usable. Radio, Nav, Sirus, phone sycning all working well for me. I am up in Canada so we don't have the sync services stuff ... so that's also a non-issue for me.
Start up time is near instant so far.. no reboots or anything like that noticed in 3 days of travel (knock on wood).
Overall ... loving it!