It's maybe worth noting I was really hesitant to put Dirt Drops on my latest build, and was going to opt for a mustache bar setup (Dimension double bend or similar) due to a prior negative experience with dirt drops. On my first bike, I was on a mountain bike with modern geometry in "my size" (a 20" frame) with a traditional angle stem. I never felt comfortable on the bars. There were a few "that's almost comfortable" positions, but invariably my shoulders would pinch together and I'd wind up in a lot of pain by the end of the week.

On my current build (see above) I got the bars basically free with the shifters and a few other parts from a friend, and figured I'd give them a shot. With the tall, short stem on a 23" frame, they fit much better and have been very comfortable on some 40+ mile rides. For the long rides with some climbs and headwinds, the drops are a nice option you don't get with a mustache bar.

I think the key to comfort with the dirt drop is having them "level-plus" with the seat (sometimes a hair higher than the seat) combined with a taller, shorter stem than we're conventionally used to on most "modern" and road bikes. If you look at the early drop bar MTB's, this is how most of them were setup from the bike shop. As always, YMMV.