It's in the old woodworkers warehouse space on Arsenal st, just across from the Hess station.
We noticed it was open last night and stopped in. We were the last people they let in at just before 8pm. However, several other people tried to get in as we were waiting for our burgers and were turned away. The guy who was the owner/manager (Wild Willie?) said maybe they need to stay open later since now they are in the "big city". Apparently, the original restaurant is in York, ME and they close at 8pm. But you know, us sophisticated Watertonians, we eat our burgers fashionably late.
It's an order at the counter kind of place, with no booze (only upscale root beer and frappes). I had kinda low expectations as the teen aged staff seemed very new and inexperienced.
But I thought the burgers and fries were really good. The burgers aren't huge, but certainly big enough for me, with a nice crispy char on them. I thought they got the bun to burger ratio right; many restaurants use huge kaiser roll-like things that overwhelm the meat. In addition, WWs butters and toasts the buns on the grill, which is a good touch. The fries were impressive- fluffy on the inside and nice and crispy on the outside.
Burgers started at $5.75 (including cheese if you want). Fries are $1.75 and $2.75. So they might be wicked good (their motto), but they're not wicked cheap.
I might add that I'm not a fan of O'Sullivan's burgers. They're so big and they cook them low and slow, so they never get that nice carmelization on the outside.