Hi Early,
Concert clubs do exist in the U.K., e.g. Nettlebed and Hitchin, but they are few and far between. In a previous existence I was involved in running a successful concert club but I will admit, they are not my favourite form of folk entertainment.
It is the people that make a successful club. Given the right club members almost any format will work. My preference is for a good singing club with occasional guests such as Herga and Maidenhead. All clubs have their good and not so good evenings but the 'wall of sound' that hits you when the singer reaches a chorus at these two clubs is why I, and a good many other members continue to attend.
Other factors obviously have some impact, the beer, the venue etc but when it comes down to it. It's the people that make a good club.