I've made a couple, and while they're good cookers, they're not without their own set of issues due to cooking directly over the coals. Not only can the "fat in the fire" flavor be overwhelming, you can actually put out the coals if you cook too much meat at one time, and you need to go easy on any basting. I only recommend using a second grate for chicken or ribs, and that's a lot easier if you use a heat diffusor.
Made right though, they're cheap and easy to make. My first one had a door, but it was more trouble than anything, and it didn't cook as good, anyway. (I figure if Weber has a problem getting doors up to satisfaction, it's certainly not worth the trouble when making your own drum since there's no reason to add charcoal or wood, anyway.) My second one had just one slider vent, so was VERY responsive to vent changes. (All you low-n-slow wsm "dry panners" would really envy how fast I could dial in temps on that thing.
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Anyway, whatever the reasons are that I prefer my little wsm over the uds, suffice it to say that I presently don't even have one put together....and I got tired of spray painting. Oh yeah, if you want to see what the "fat in the fire" flavor is like, just trim a little off the fat caps and toss on the coals periodically on your next cook.