Thumper,

Even though they are French, Chapuis is hard to beat. Have a couple of them and love them. Merkel is OK and not quite the gun a Chapuis is. Heym I haven't owned but I like the looks of them. A lot more money too.
If you are going to hunt with it get ejectors. Makes reloading fast. Go with a rimmed cartridge. Dust will clog up those little extractor pins in a rimless or belted ejector. I have a 375 H&H double thats so far has ejected fine but just don't trust it for dangerous game. Don't want an empty under the ejector.

Sam