I've only been there twice so far (having a 9 month old limits my time downtown, I'm actually over in Endicott), but I have been impressed with the beers I've had there. They had a really great weisenbock on tap when I was there during the winter that I've been craving, but it isn't available now. They also have good food, the falafel bites and jalapeno cheddar hushpuppies are awesome. From what I hear, it's usually pretty busy there. There's actually a couple breweries that've popped up. If your friends haven't checked out the North Brewery in Endicott, they should, that's my go to place. Should let them know, however, that there's no pints or food, just a 5-beer tasting and growler fill-ups, and usually not busy, however I go in the middle of the afternoon.
P.S. If your friends here brew, they might like the one in Endicott. I'm pretty sure the guy there would be more than willing to sample their beers and discuss. I don't know how bringing your own beer would go over at Water St.