Both brands have a good reputation. Personally, I would take the Merkel, as it appears to be the better deal for someone who is cost-conscious.

However, double rifles are for fast, reactive shooting. Therefore, I would get my hands on both of them to see how they mount and handle for you. First, pick one up, close your eyes, mount the gun in one fluid motion and see how the iron sights line up for you after you open your eyes again. Ideally, the fit should be like a well-fitting shotgun, with which you shoot where you look, without the need to correct the mount. Then swing and point the gun, - if it feels like a natural extension of you, then it's the one you need to buy. You can have SLIGHT modifications done to the stock to make it fit you (short of restocking completely), but a gun that feels like a cooked noodle in your hands will not give you the satisfaction that shooting a well-fitting double can give you.