As much as I'm a reggae fanatic, I don't think any of these guys were much more than adequate players, and weren't any better than dozens of guys you could find in any average American city. I like the fire some of them showed in the early days, but their playing clearly atrophied after the ska era died, probably because there wasn't much soloing, mostly just playing figures, and the changes in the later songs were pretty simple.
I had Tommy McCook on my radio show and he told me had just been visiting with one of his Alpha School fellow alumni who had moved to England where he was a jazz player (I forget the name). I asked him if he jammed with the guy, and Tommy said "no, I don't play jazz any more". I asked him why and he said, "because you have to practice".