I've got three, an old bronze 90/0, a newish steel 115/2 and a duckbill 120/0. (0 is brightest, then 1, 2 and 3 is usually a special order item). The bronze one and the duckbill are both UK made. I don't know about the other one - current production is in Belgium, I think.
I'm not too sure about the tales which abound on certain US boards about huge variability of Bergs (and other mouthpieces as well). I also just don't believe the hype peddled by mouthpiece refacers that all mass market pieces need 'perfecting'. I've got about thirty in total, and all play fine out of the box.
Anyway, I digress. I like Bergs, they tend to be bright, punchy and easy to blow. Of mine, the bronze is nice and bright, dead easy blow. The 115 has a full tone, quite fat with a bit of brightness. The duckbill is a rock n roll monster, loads of oomph and volume. Tend to work well with Rico Jazz Select. The duckbill can produce enough volume and brightness to knock a wall down with Rico Plasticovers.
Jon