I'm in between double rifles right now but I am VERY close to buying my next one. I am very impressed with the O/U rifles I have handled. The seem to be very accurate and handle very well. Some people make a big deal about the amount of gape when the rifle is open for reloading. The argument being that the slightly wider gape of an O/U rifle slows the reload. Maybe, but if the gun has ejectors a reload can be done so fast that I hardly think there is much perceivable difference. O/U double rifles may well be superior in many ways to SxS double rifles so really it is a matter of personal preference.
SxS doubles LOOK sexy and are preferred by many. They are just classic and romantic. The O/U's have a lot going for them. I love the O/U's and eventually I'll have several probably. But my very next will probably be a SxS. The one after that an O/U. That's where I'm leaning at the moment,
I like Verney Carron's and in an O/U you can get a nice one for $10,000 or less, you'll just have to not go overboard on the upgrades. VC is a GREAT company. They are not cheap but they are a still a great deal. $30,000 will buy you a rifle that is just as nice as a $130,000 rifle from London, IMO.
I also LOVE Chapuis and Merkel.