Hey killerman,
I did Month of Mayhem with Liam, and I'd say it was worth it. His fundamentals are on point and his teaching helped me tighten up my own game as well (that was about the time I got over a sticky point and "leveled up" my results). Their school of thought is a bit like the stuff you see here on GC, but it's nice to see in person with a teacher to guide you.
Liam's also just a cool dude that genuinely wants to help people. He gave me a job or two when I was just getting my feet on the ground in Melbourne that helped me out financially (one was doing sales for TNL, actually - though I'd like to think this recommendation was unbiased)
If there was one thing I wish Liam did, was show a demonstration approach or two. But perhaps he's just relying on his YouTube videos for that.
My friend did a residential him, and he slept with a few girls on that particular weekend (he was already pretty good)
Hope that helps
~Nick