I'm with GP on reliability though - I'd rather have a can of a known bitter than a local 'IPA' on tap that I don't know (and the other side of the bar doesn't care, or share a common language to decide) if is a 'proper' IPA, or one of these very pale, extremely fizzy things that seem to be in vogue and call themselves IPAs, when to me they're closer to a lager and almost any (non IPA-style) bitter would've been closer to what I expected. Sometimes I can tell from the label it will (or I fear it will, so don't try and can't say for sure) be like that, but certainly not always, and that's not always practical.