There's no lag on any of the new Zoom units AFAIK. The tuner is good, the compressor is good (but that's subjective). I've never been able to get the XLR output on mine going, but I only tried after i'd dropped it quite hard which also made the switches quite unreliable.
I love the sounds, the interface, the switching, the tuner, but I will have to put some heavy duty off-board switches on it to gig it again (which I will do). Perhaps someone else can help RE the XLR.