If you go to the beer/ale aisle in any of the large supermarkets here there are a lot of American crafts represented, from the bigger ones like Boston BC or Sierra Nevada to the smaller ones. In terms of sales I'm not sure how well they do, as they clearly have import costs on them, they are 50p-£1 more per bottle in my experience, and so the casual ale drink will more likely go for one of the many local/national variants. In terms of production and method the Californian IPAs and APAs in particular have definitely breathed life into the industry.