I've got 7 PE, and actually for me, it wasn't a huge leap up from 6 ... largely because I don't go that deep into the programs huge feature sets.
Yet, 7 is better. It's faster. Bouncing tracks down takes half the time from previous versions.
The synth sets and new plugs were worth the cost of the upgrade alone. They're really good, and I'll continue to support Cakewalk as they upgrade their flagship product. To me, it's worth the investment.
I suppose someday I'll use some of the extra features, and be happy they're there when I do ...
Best,
Kev-