You know, I thought Revelation of the Daleks was pretty good -- good enough that it makes me want to check out more Sixth Doctor episodes, which I hear is an emotion most people rarely feel.
Aaaaand Mark of the Rani has cured me of it.
The setting is interesting, and it's got the Master, and the Rani is a character with potential, but...it's pretty much terrible. At this point I want to punch Peri in the mouth every time she opens it (though this actually makes me kind of want to check out Trial of a Time Lord just to see her die).
The fact that this is regarded as one of the better Sixth Doctor serials goes a long way toward explaining why everyone hates the Sixth Doctor. Not worth buying, not worth renting, not even worth watching while drunk.