I do like Resolve, but it is super hungry on my machine it really struggles. By far the most control, the trackers that it has are amazing but be prepared to loose a lot of time messing around and learning. I was over at a post studio last week and watching a pro colour guy working on the footage with the Resolve control deck was pretty amazing, there is so much to learn hence why people get paid good money to just be a grader.
Colorista is pretty straightforward and with MB Looks you can create some cool stuff albeit a little cheesy. You can download them as a trial to play with.
Never used speedgrade or the others