Not that I noticed, I gigged it Sunday night - some ludicrous stuff going on (up to five simultaneous effects on each unit possible) but latency didn't appear to be a problem My fabourite was a distortion featuring octave up, octave down and several overdrive, big muff type stuff going on Along with noise gates and compression As I say ludicrous but enormous fun. My original idea was to collect ms-60b pedals and do a board full of them but they're harder to come by. Still planning to do it over time.
The experience of using it live actually taught me a lot about what I really want to bring in and out and what is less useful. HPF, volume boost, compression, some kind of ott gnarly distortion, envelope, chorus and an always on tubey subtle grit. Occasional flange and phaser effects are useful as are octave and synth sounds but less useful than others.
I think two B3 units would be awesome. Just to deploy as six standalone pedals.