Full disclosure, I have several 303-type instruments...an Aira TB-03, a homemade X0XB0X, a darkstar rackmount, and a eurorack X0XHeart.
The TD-3 MO is lots of fun, but I'm still getting used to the Behringer style sequencer. It's not quite as hands on as my X0XB0X (which has some heavy mods) but it is far more predictable when tweaking. I like how light the TD is, and I find a bit of velcro is all I need to stick it in a weird place, so it makes it into more of my "away" jams. For the price, it's a solid piece of kit, as long as you aren't a purist about the 303 sound (and why would you be?) I'm still learning how to get it to play nice with some of my gear (sometimes fiddling with the PPQ helps) but mostly I use it as a triggerable secondary bassline...almost a bit of lead sound, as it's very playable. Fun times.