After the many posts and the locked thread, it seems the best option for Construct users now is to wait and see how the subscription turns out. Scirra really wants to try it, and if it works out then that's great for them (and us) !
If not, they'll hopefully have a backup plan ready in time
But, I would say it will be one or two years from now before we know for sure (eg: many people might try one or two years before trying something else, so it's still pretty risky for Scirra if big/long-term projects aren't being made).
That's okay though, we've all been waiting many years already for HTML5 to be the high performance multi-platform export format of choice for 2D gaming anyway, what's the harm of waiting a few more?
The problem with this I think is that at the moment there is actually very little incentive to subscribe. The overlap between C2 and C3 is vast, and who knows how long it will take C3 to mature enough plugin wise for many to transfer their projects over? I say this as someone who is knee deep in 3 projects, all of which use plugins qhich quite frankly should be part of the base construct package. If I subscribe in the near future I'll pretty much just be throwing $99 away (or whatever discount I get from being a customer) the only incentive to subscription at the moment is support of Scirra's vision, but unfortunately some of this vision I'm not interested in. I think people will continue to discuss and criticise this model and that won't go away. We're not stirring a frenzy, the fact is it doesn't fit the needs or wants of the greater community.