Judging from the types listed here there is a clear age demographic to this forum!
I have flown and instructed (civvy and military) Tiger Moths, Chipmunks, Bulldogs, Fireflys, JP 3,4 and 5. Of these technically only the JP is a basic trainer although as mentioned above it essentially doubled up when the RAF did "straight through "jet training before reintroducing a grading system.
In my view the best iteration in recent years for RAF flying training was when a screening process took place on the Chipmunk at FSS (or on a UAS if they were members) followed by a 100 hour BFTS course then streaming to either Gp1 Phase 1 and 60 more hours on the JP or helicopters/multis. Sadly this was deemed too expensive.
To answer the original question, as a basic trainer I enjoyed flying the JP 5 more than its other variants. Lots quieter and somewhat slicker so although the 4 gave better initial acceleration once drag became a factor the 5 would pull away. That said the tadpole nose made it more difficult to aerobat than the 3 and 4, particularly as stall turns and their variants were such a big part of its repertoire. It was not particularly well harmonised though with stiff control forces and a relatively poor roll rate.
Of the primary trainers the Chipmunk would be my firm favourite and is quite simply a delight to fly.
Ok, that's all the old duffer stuff out of the way and everything I mentioned above was when flying training was designed to lead you to a front line aircraft that was DIFFICULT to fly. The theory of the day was that the better you were as a pilot the more spare capacity you had available to operate the aircraft. These days those aircraft are gone and we have aircraft that are relatively easy to fly but equipped with complex mission systems. So it could be said that the converse is true, we now need someone who is an ace at the mission systems but no longer requires the same level of basic flying skills.
So something that is fairly easy to fly but packed with screens and electronics may now be the way ahead?