Can't speak for the 37 but we had a BMB 34 last season. They are not that different I don't think (having seen the 37 at the London show).
We were very pleased with the 34 - good sea-keeping and handling in some reasonably tough conditions. Usual few niggles to start with but reliability good from then on - nothing major went wrong. We did nearly 160 hours on her last year so she was well used.
The fit-out is a bit more basic than some, but sturdy and I think that's reflected in the price. PM if you want any more thoughts.
Have had BMB 32 moored next to my boat for last year. owner now has it on market due to emigration but likes the boat a lot, Good value for money. However is a bit of a beast to get on and off when not mooring stern to. This is due to the fact that the bathing/boarding platform does NOT go to the outside edge of the hull. This means you have somewhere around 18" plus the width of whatever fender you choose to use at the blunt end, to step over before you reach a pontoon. If if you are 18yrs old, fit and the pontoon is dry, it wont be a problem. Anybody else under other circumstances will not find it easy. Refer to MBY report May 2004 for write up on 37'. Good hunting. P