They both have their pluses and minuses, but in the end I guess I liked
ROTS a little better. Overall,
ROTJ - Started out very lively, got bogged down with the frakkin Ewoks, and the idiotic idea of a second Death Star. Leia being Luke's sister was revealed in a very underdramatized way. Luke seemed "off" overall - probably because his character development happened between
ESB and
ROTJ, rather than being dramatized, so it was hard to know exactly who he was, by this time. His final confrontation with Vader and the Emperor was handled reasonably well, but the musical chairs with actors depicting Anakin destroyed the emotional impact of Luke taking off the helmet and the ghost scene later.
ROTS - Still had all the fatal flaws of the PT, namely that Anakin was depicted as such a putz, it was impossible to care what happened to him. By the time they got to Mustafar, I was just rooting for Obi-Wan to push the punk in the lava and get it over with. But the action in the last half was okay and it was nice to finally see that Mustafar stuff after having heard about it for eons. Padme's death is the single stupidest thing in the entire franchise, but the final scenes with the twins being delivered to their adoptive families was a nice way to end the movie.
After looking at these synposes, I think I should have voted for
ROTJ.

Oh well.