The Alesis MMT8 is a nice toy 
Problems with Renoise AND Seq24 will start (IMHO) when you start Jack. Using Renoise purely with Alsa is so fast and smooth … plus the developement of seq24 is a bit behind to write in gentile 
Renoise handles Midi very well incl. MCCs. It has not the “loop of different length”-thing, but actually the only thing I miss to come close to this kind of workflow is a Renoise-feature that “cues a track for mute” Cue For Mute
Handling loops of different lenght is so different to the way Renoise works, that it is impossible to implement without a complete rewrite of the core … but I can miss that…