To me it makes sense to compare the features and timing between X1 and X2, then X2 and X3 and then look at the upgrade pricing for those new versions. I came to the conclusion that the new model is pretty much in line with the previous way of shipping a new version every year or so. So for me, cost-wise nothing has changed much, give or take a few bucks on the renewal price.
What has changed is the regularity and frequency of fixes and the scope of new features and content that have been and will no doubt continue to be shipped. In terms of features, I think Cakewalk has exceeded whatever bar they may have set for themselves in new functionality, and personally I'm impressed as hell with what they've accomplished.
As for bugs, I don't recall any product of Cakewalk's that received twelve fix updates in a year before they shipped a new version, does anybody else? It would be great to see some stats on the number of bugs fixed this year so far. I'd guess the numbers are higher than the typical numbers in the old model. And unlike in the old model, the fixes will just keep coming and they won't ever stop.
So yeah, to me, renewal is a no-brainer.