For those worried about 3rd party addons, I wanted to point out Overboy is right about stability in c3. For all my complaining about the engine, c3 is the most stable tool I have worked with, and though I do most my work in unity...
I think 85% of the add-ons I have bought in unity are depreciated or irrelevant at this point, and those sometimes easily cost > $100. Was it a waste of money? Depends on how you look at it.
If you can benefit from a tool now, the worst thing you can do is not buy a tool simply because you think it will be outdated in a few years. You'll find yourself under-productive, waiting for an off chance that something will change. Also, the standard workarounds for the tool's Overboy is selling aren't as performant or nearly as convenient.
Get 'em while they're HOT!!!!
If you work on medium/large projects I think you will find them indispensable.