The tracking of grading "windows" and so on looks pretty convenient (of unlimited number too. Computer power relative of course). And the softness of the edges on those areas seems simple and seamless. You can do that sort of thing in After Effects or something as nicely of course but it's not so dedicated. You're stacking functions to do it.
Actual colour controls seem pretty much standardised these days. There's probably subtleties, but in 32bit float most of your RGB abstractions are pretty much the same. I guess its just a matter of whether or not you like the resolution of the colour wheels and curves and so on in a particular interface and whether or not how they're arranged works for you (Color Finesse has more flexible curves than the stock AE ones for instance. Mostly I'm in AE of late, as you can see). Colorista has grouped things in a way to make adventurousness a bit more at your fingertips I guess.
Ultimately it seems like you could do all the same stuff with enough work on stock AE effects, for instance, but it's just not as convenient. But I've usually got something specific in mind or I'm just trying to match things up and not in any great hurry, so perhaps not hard core enough to really give an in depth answer.
