I've only used it for about 10 times and i allready love it.Compare to mark 2 has got good few extra features:
-the effect could be edited,you could set up the number of milisec onds on delay or you could use the tap tempo button,etc.
-nice filter for bass
-built in sound card that could be used through usb(audio digital interface), midi ports.
-it could record 4 chanels simultaneous,just need a laptop(comes with cubase le)and ready to go.
What i don't like about it is the side handles and plastic cover could've been better quality.
Overall it's a very good mixer.I'm delighted with it