Mike,
I'm with you I always shoot O/U better than S/S which is why I have no S/S shotguns,just am not effective with them. That being said I personally would have no objections with an O/U big bore and the single drawback with the Browning you are talking about to me is the inertia single trigger. If it can be converted to manual I'd go for it. The fact that it's built on a shotgun action would make a difference MAYBE if you were going to put thousands of rounds thru it but if you are like most of us (which you probably aren't if you have an H&H Royal on order) it will be more like hundreds of rounds at most thru it. It's not exactly a plinking gun you know. I see no severe drawbacks, but the traditionalists on here believe if it's not English and a traditional builder it is of no value or quality. I personally liked the Valmets I owned as far as performance went, esthetically they left a lot to be desired. They were only 9.3x74's but really handled nicely,far better than any S/S I've owned. As I say I'm a majority of one but if you like it get it.