Ben Sherman suits have an interesting history, combining mod fashion with Savile Row.
They were founded by Arthur Sugarman in the early 1960s. They were one of the first companies to get in on the American Oxford shirt style craze that was big in Britain at the time. They started making their own for the English market, and then moved into the suitwear game. These ended up being very popular as well and meshed in well with the mod fashion that was in style then.
Today they are very tough to get in the States. No mainstream department or men's fashion store carries them. They do have their own stores, which right now are in New York, San Francisco, Las Vegas, Boston, and Beverly Hills. In past years they were available at Nordstrom's and Nordstrom Rack, with an occassional sighting at Macy's. They are almost always on sale and can be had for $200-$300. This is a pretty good price especially if you are going for a slightly hipper look.
As far as the quality, reports are mixed. They are mostly fused but many guys say that the quality is pretty decent. They generally use decent fabrics such as Super 110s. The Arnold Brant label, which is supposedly an identical style, often has the same look but with inferior fabrics, so look out for that.
Even today, a lot of their styles have the mod look to them. They have the skinnier look and shorter jacket length that was popular in the 1960s. Its definitely more suited to the taller, thinner guy.