As a reader I like the "Wait till the last minute to reveal the villain" type stories. Sure I fuss at the author at the time to tell us who it is, but I have so much fun trying to guess. I love speculating with other readers about who it could be. I usually don't mind the pages of him explaining himself because by that point you have me so curious that I have to have some answers.
A mid-story reveal works for me as well. That way I have a bit of time spent in suspense over who it is, but then later I can enjoy in knowing what is going on. Knowing a villain is up to something and Lois and Clark are about to walk into it is almost as suspenseful.
The knowing ahead of time... hmm. Sadly I have to say, I'm usually only paying attention to b-plot at that point since the a-plot is pretty much known and I don't have to fight for it. Knowing ahead of time who it is makes me anticipate the kinds of things they might do based on the series. Unless it is a totally new villain you have made up. So I naturally move to any romantic aspect going on. These were the stories that I skimmed the first time though the archive. (I just hit ctrl+f and look for kiss LOL) I've since gone back and read a great deal of them but yeah... you get the picture. I'm impatient and if I think I know how it ends I just skip to the steamy parts.
And blue. I like blue.
