A:Answer I own 2 7 series and 1 6 series Samsung TV in my home. The major differences are mostly negligible but I have found:
3 HDMI ports on the 7 series but 2 on the 6 series
6 series cannot connect to 5GHz networks, only 2.4GHz (7 series does both)
Stands are smaller on the 7 series (6 series take up a bit more room)
The bezel is smaller on the 7 series thus looks a bit nicer.
Button access is better on the 7 series remotes (dedicated Netflix, Hulu, etc) unless you have the higher end 7 series, which has a minimalistic remote.
If you play fast paced games, the 7 series has lower input lag.
I hope this was helpful.