An interesting thread. I make stove top AG following Clibit's "have a go...." thread, and I've made about 50 brews so far. They've all been fine, better than any kit beer and in some cases better than a lot of pub beer. Except for brew number 2 where I left the lid on - it tasted of cabbage. (still drank it tho' :whistle:).
My method is pretty rustic, so there are many variables that could have contributed to this particular brew finishing up below par. But I haven't had the problem again, and all my other brews I've left the lid off. So although the brulosophy article is interesting I'd need more proof before risking another batch to the posibility of boiled brassicas. Using a stove top method it would have it's advantages - easier to reach and maintain the boil and (hopefully) reduced levels of steam in the kitchen...
If the lid wasn't the problem, what else could contribute to the off-flavour? are some malts / hops / yeasts more prone to these sorts of things? Pitching temperatures? anything?