I haven't mounted a laser sight on my CFX just yet, but thanks for helping answering my own question before I even asked about which laser fits the rail below the muzzle on it.
As for vibration, I suspect that you might get somewhat less vibration on the scope rail, but who wants to sacrifice using the scope for a laser instead?
I suppose you could remove the scope and use the laser instead if you really want to, but I think (haven't done it yet, sorry) that having the scope as a way to analyze where your laser is illuminating would be quite useful for placing your shots.
As for durability, I seriously doubt that your BSA laser will fall apart, just as long as you keep it securely mounted and don't allow the battery door and other possible areas that could come loose snug.
After all, it WAS designed for airguns, so I don't think it will just fall apart.