Careful use and absolutely NO shock loading on any winch mount option should afford you years of good service, with either mount options. The choice is really out of convenience and storage capabilities. With it on the bumper, its always there and ready to go. If on a cradle, you have to store it, and haul it out as required. Leaving it on the receiver hitch is not a good idea (in my opinion) simply because it really hangs out there and is open for potential damage. If you know you are headed into a precarious situation, you can pre-game by mounting it up.
Mine is currently mounted on the bumper. But I have been thinking of cradling it so I can just have it loaded up when headed out on adventure. And leave it safe and sound in the garage when daily driving. Plus it will offer the option of reverse winching without all the rigging.