Not a bad burger, just a little pricey. I had the Shack Stack burger which is a regular cheese burger with the 'shroom burger added on top. It's cheesy and tasty. Added a side of cheese sauce for the fries and not bad.
It has a limited menu, four burgers and three dogs, but it has custard "concrete" shakes and beer & wine too.
Bottom line is its good (for a burger) but not cheap.