My Merkel 500NE double is my favourite Big Bore. It's heavy enough to tame the recoil to manageable levels and it has near perfect balance. I can also find the sights very quickly with it.
I still think I might need a 500Jeffery bolt gun, but none of my friends have one, so I can't try it out. I did fire a friends 505Gibbs and discovered that went beyond fun for me.