I think there's little doubt that all the composers Star Trek employed were very competent. Most of them got a chance to show off on Enterprise (where all the musical rules were seemingly dropped, maybe out of desperation because the show was failing).
I also enjoyed McCarthy's and Chattaway's early work on TNG, before they got muzzled. And Ron Jones, of course.
McCarthy did a very early score for SG-1 which greatly entertained me because it sounded NOTHING like his Star Trek work at the time. Very percussive and exciting (and sadly synthesized but that wasn't his fault).