Inevitable I guess.
I agree with @pidgeo that the fx on the tb-03, well the dist/overdrive anyway, sound absolutely crap, the delay is good and reverb just ok. I think the tb-03 synth sounds pretty good, definitely suited more to higher acid lines though especially when compared to my self built x0xb0x, TT-303 and real TB-303s.
The tb-03 definitely has some advantages though, it will be interesting to see what the Behringer will bring to the table, and if they get the sound right, which based on their previous “tributes” could go either way.
The Volca Nubass could be a bit of competition for the Behringer, it is an interesting acid synth in its own right, and since we are on the Elektron forum the A4/AK are great for acid, well worth remembering if you have one and you don’t want to buy any more stuff 