There are more S6 episodes that I like than S7 I think, because for me S7 wasn't that strong at all but I feel that S5 was the last season of the show to be broadly and consistently stronger on average. I think it was one of the peak seasons around that general peak of S3 - S5 that TNG had.
But on balance I would always take the first two years over the final two for the most part.
'If the Apocalypse starts, beep me!' - Buffy Summers
'The sky's the limit.....' Jean-Luc Picard, 'All Good Things'
courtesy of Saquist