The interesting thing is that Vista and 7 are substantially identical - same interface, benchmark about the same ... but people typically tried out Vista in 1GB and 7 in 2GB.

And businesses I saw moved from XP to 7 mostly so they could use more than 3GB memory.

YMMV of course. But as a parallel, remember that the Edsel is famous as Ford's greatest failure, and its followup the Comet as one of Ford's greatest hits ... but the Comet was a reskinned rebranding of what was going to be the next Edsel.