I average 2 of each a month.
Just 2 weeks ago, they had a 6505+ head for $600, which is already a great deal.
I had some pedals that I wasn't using so I took them there and they gave me $400 for it. I also had a $50 store credit from a previous purchase.
They even adjusted the price so it would be 600 out the door (after tax).
So I walked out of there with a 6505+ for 6 pedals I wasn't using and $150 out of pocket.
2 weeks before that I got a 1987 Charvel Model 6 for $325 because it needed some very simple wiring work.
On the sell side, I had a Les Paul Traditional that I was trying to sell for $1500 on Reverb. It sat there for 2 weeks with nothing but tire kickers messaging low ball offers. Took to Atomic Music and they paid $1200 cash on the spot. Probably about the same I'd have made on Reverb after shipping and their fees.
It's almost like trading with private parties except this private party has a giant warehouse full of stuff and it's a cool guy to boot.
They also have an awesome in-house amp tech that used to work for Mesa Boogie.
Did I mention I love Atomic Music?