This is one of three G Lab devices I have, and like the others, it is really well made, and very reliable. It's more or less a permanent part of my rack setup, and uses MIDI commands from my G-System to instantly switching four stomp boxes in or out.
The G-Sys only has four pedal loops (three if you're using a multi-amp setup like mine), and it isn't perfect. The G's loops are after an input buffer, so they mess with old school fuzz pedals, and the switching isn't instant - there's a noticeable (albeit very short) delay with its relays. Enter the G Lab MIDI switcher. Four loops in front of the G-Sys's input, completely passive signal path, true bypass, and no delay that I can detect.
This is a great little box, and I'd recommend it to anyone with a MIDI rack setup that includes stomp boxes.