Right, it's a 3o3. We don't need to talk about the sound - if it's 3o3 sound you want, you get that here; check out sound examples online or in-store, completely ignore the weak "distortion"/"drive" combo and do what the big boys did, riding it hot into an old mixer; complement with overdrive/saturation/fuzz pedals to taste: voilà!
With the sound out of the way, how does she handle?
We're getting full-sized audio out and MIDI in and a combined out/thru, which I really appreciate after too many mini-jacks, and jack-to-MIDI-A, jack-to-MIDI-B adapters.
Programming her can be done in the classic way, or via software provided by behringer, which also takes care of firmware updates and such. I've only ever used the Widows version; it is functional.
Finally, you can send note events and sysex via MIDI, and have rudimentary control over accent and slide via velocity and legato playing, but of course no automated filter sweeping madness. This box wants to be used hands-on.
Combined with an MAM MB33 and a few effects for grit as stated above, this yellow box ticks all my ... boxes. I know there are successor models with more CV modulation capabilities and overdrive and whatnot, but I am very very happy with this MK1.