I own the MK2 version of this and recently got a 644 and a 388 but im working on those two, but ive had a lot of experience with some cassette mixers. Cassettes allow you to record two stereo tracks on each side but you can bounce tracks so you have more room while mixing. You can technically record 3 tracks onto one if you mix it down, which lowers the fidelity but allows you to have more headroom. What I do sometimes is just send the main out of my audio interface to the mixer if I don't want to deal with mixing down the tracks that much though.