I've been using Construct 2 casually for years and recently upgraded to Construct 3 (so I could work on a Facebook Instant game). I'm not a power user, but I haven't noticed it being limited at all. Though, I guess it may not have as many addons as C2.
To be honest, I thought the whole "runs in the browser" thing was kind of gimmicky but the work Scirra has done on this is damn impressive. And the other night I was doing some work before bed and right after I climbed under the covers I thought, "Oh, wait. I think I know how to fix that problem I was working on!" I pulled out my iPad, launched Construct 3, fixed the bug, and saved it. Worked like a charm!
My only real concern about Construct 3 was the yearly fee. I tend to use these kinds of tools for a few months and then not at all for half a year or more. But I got a C2 discount on the first year so I decided to give it a try. So far so good. And the new faster runtime Ashley is working on should be great! (That's a C3 exclusive, I believe.)