I had one on on board but I sold it when I bought a Skreddy Mayo. I have a Big Muff NYC if I need that particular Muff tone again. The LBM and the NYC are so close as to be practically indistinguishable. I kept the big box NYC mainly because it reminds me of the first Big Muff I owned and eventually modded to death
Big fan of the Little Big Muff. I've just started up a guitar gear video review site and my first review was on LBM! It has a smaller footprint and tone is very similar to it's bigger brother... and you're right you can't beat the price. You can check out my review here if you're interested: http://www.thesoundchecksessions.com
There's always a slightly better Muff out there, so I'm not surprised that most of TGP doesn't use the LBM. I myself replaced it with a Barber Trifecta. But the LBM is definitely a good pedal, and the price is right.
The LBM does a certain type of Muff tone very well. I never gigged mine because the scooped mids made it difficult to cut through in the classic rock band context. It's quiet, it's cheap, and it is a Muff. It's just not my cup of tea.