David Bell and Jay Chattaway were my favorite Star Trek composers but yes Bell was the most repetitive! I could usually tell within a minute or two that it was him scoring the episode.
Gee, I could usually tell within a couple of bars which composer it was. The orchestrations and rhythms that McCarthy, Chattaway, and Bell used were very distinctive. Bell was particularly easy since he routinely did his Trek scores in waltz time. I think he also used more French horns than the others. McCarthy was big on brass and strings and used pretty steady 4/4 time. Chattaway also used a lot of brass, but less solo trumpet, and less cello and bass than McCarthy; he also tended to make more use of long sustained notes and varying or syncopated rhythms, without the same kind of driving ostinati that the other two used.
The one big V reuse I remember McCarthy doing on TNG was in Encounter at Farpoint. The fanfare he used for Q's entrance as the judge was also his fanfare for The Leader in the final episode of V. Other than that, he mostly only used his military snare thing on TNG sometimes.
Oh yeah, I discovered that recently, but had forgotten.