Unlike the other reviewer I have never tried their milkshake, so I can't comment on that. The burgers however, are really good, specially the mushroom special ones. To be more precise, I've tried both their "Grilled Mushroom 'n' Onion Double Steakburger" and their "Portobello 'n' Swiss Steakburger". In fact, this is my favourite burger place in town, which is conveniently located on the way to the Savoy 16 cinema.
And it's kind of cool to get waiter service in a burger place.
BTW the prices are reasonable. Not as "Green street cheap", but not too pricey either.