There's good beer in all varieties, and terrible beer as well. The rule of thumb is to avoid stuff you've seen advertised too widely, and when it comes to draught beer, avoid anything that isn't hand-drawn.

There may conceivably be some good lager produced in the UK, but I've never come across it. So I'll stick to (some) imported lagers and some English-style beers I've got reason to trust. And Guinness, but preferably Murphy's if they have it. And of course I'll be happy to sample any of these hand-crafted American beers if anybody's buying...