From best to worst (personally):
-Return of the Jedi
-The Empire Strikes Back
-A New Hope
-Revenge of the Sith
-The Phantom Menace
-Attack of the Clones
And some other points:
From a structural level, I think Empire is probably the stronger film. There's less cons to Empire than Jedi, but IMO, the pros of Jedi are enough to give it the top spot, if that makes sense.
A New Hope and Revenge of the Sith are close for me as well, but it's kind of the opposite, in that A New Hope is the tighter film, but Revenge of the Sith is the more watchable one, and easily the best of the prequels. Overall though, I have to give it to a New Hope, because while I do consider RotS to be a genuinely good film, it's still a very flawed one.
Prequels as a whole...truth be told, I've never been that enamored with Star Wars - yeah, I enjoy it, but that's about it. I saw the OT in cinemas in the 1990s, and I saw the PT when it came out afterwards. Looking back, and after Red Letter Media, yeah, they're very flawed, but I can't call them horrible. There are far worse films out there for me to descend into a rage over the prequels. So yes, I enjoyed the prequels at the end of the day. But that said, since I'm making a list, I'd rank PM over AotC. Of the prequels, PM is an average space adventure, RotS is the epic, whereas AotC is the awkward middle child.
But that's just me.