I'm running Windows 7 too and got no really special problems with Platinum, with the exception of a bug with Kontakt5 in non-english windows localization.
Platinum is stable as X3 was. Some of the new features are nice and timesavers.
The new membership program sounds good. Hopefully, Cakewalk will meet the expectations and marketing messages.
Is it worth? Hmm, yes I think so. But this is relative to my own perspective.
Is it worth to invest some money in a software that you use regulary and you want to get the best of it? If yes, buy it.
_Markus