What stands out to me in all this marketing hype is, as soon as you stop subscribing, you only own the prior version and the latest beta test version. This is not the same as the marketers' claim that a year subscription buys both versions X4 and X5. In truth, the X5 version will not come with bug fixes unless you continue to subscribe. Nobody is getting anything free here.
Behind the scenes, the marketing folks understand, once you buy into the subscription, you will be locked in for life. You will always need future bug fixes for your latest beta test version. In order to stop subscribing, you would first have to identify the most stable point to rollback to. Cakewalk's goal to create a perfect piece of software at any one point in time will be shelved in favor of the hotdog on a stick approach. Hey, just pay for one more month, and you might get to a stable point that allows you to stop subscribing. Oh, you didn't get there yet, well just pay for one more month, ad nauseam.
New feature releases will follow the same hotdog on a stick approach.
That said, if I didn't already own full versions of TH2, etc., I would upgrade immediately. As is, I'm going to hold off and continue to use my stable version of X3 for awhile. Since I only upgraded a couple of months ago there's plenty here to keep me busy.