The best thing about the TB-03 is full midi cc control and the extended note range, as a clone it gets fairly close, probably IMHO closer than the TTmkII and TD-3 (I have a TTmkII, and it definitely has its own strengths, so bear this in mind) I don’t have a TD-3 (no surprise) but it seems to sound ok, but not too close to a TB from what I heard of the various demos. But the other thing to think of if you like acid/303s it is nice to have a couple of different ones, one for leads one for bass and one for mid range acid, you can fit 3 or 4 into a mix without too much trouble if you are mindful of note ranges and filter settings as well as eq, fx etc.
I’d like to try a RE-303, the Avalon and the Acidlab one.
@pidgeo how are you liking your RE-303?