Man this is such a wholesome thread. Just wanted to add my $0.02 on the twang issue.
I don't think we've ever disputed that liquid extracts can tend to have a twang. Every method of brewing has its pros and cons, none is the "right" way to brew. The advantages of HME are that it's great for beginners to learn on, doesn't take much time, space, or equipment, and I think the smaller batch size is an advantage to a lot of brewers. The disadvantages, as I see them, are less control over some factors, darker color, and occasional twang.
To my palette, some refills have more twang than others. I get more of it with Diablo than Long play, and more with Blonde than Weissbier. So, that's one factor to consider. Another is that doing a grain steep or hop boil can reduce it pretty drastically. I find that more important than temp or sanitation, in terms of the twang aspect.
I would also just add that I've brewed hundreds of HME batches by now, and only had a few batches where twang was strong and unpleasant enough to impact my enjoyment of the beer. Given our policy of replacing bad batches and, I think, our flexibility, I find that to be a pretty low-risk proposition.