i went to checkout both bindings at my local shop this week. the union's felt a little cheaper. it seemed just like a basic, sturdy binding that will handle anything you throw at it. the rome on the other hand felt like an upscale binding. the asymmetrical highback just makes sense and the straps bend away from your boot avoiding stepping on it when strapping in. the cant beds are a nice option and frame flows well and under the binding which has a nice and soft base probably absorbing a lot of chatter.
since i'm looking at forum and capita boards, it'll be a tough choice too. both bindings will handle what i need them for, but union's go with capita's like pb and jelly. i really wish the boss' came in cyan for both bindings, not mixed with white on one binding. can't go wrong with each.