ROTJ is a poorly-conceived movie with ridiculous plot holes and a shoddy structure, that is totally rescued by the wonderful additions of two memorable characters: Jabba, and the Emperor. Every scene with those characters in them are marvelous, and the juxtaposition of a wrinkly old evil sorceror with this high-tech space battle is fabulously done. The climactic scene with Vader, Luke, and the Emperor is on a par with anything in the OT. So despite its flaws, I still rank it close to SW and ESB. I think anyone who puts ROTS even close to ROTJ must be looking through strange glasses - it's not even close. My ratings:

SW - 10
ESB - 9.5
ROTJ - 8.5
TPM - 3
AOTC - 2
ROTS - 2