One issue I have with a hitch-mounted spare is that the hitch can't be used for anything else like for towing or for a hitch-mounted bike rack. If your hitch doesn't serve you in any other way, then good for you.
Since others are sharing their spare tire storage means, here is ours, tastefully stored out of the way. It's bolted in there solid, well protected from the elements and under lock & key. For the record, there is inadequate room under the rig behind the rear axle. I think it allowed the RV manufacture more flexibility in floorplan design of their various models without giving up the spare.
mrnoyb,
I would install a "Quiet Hitch" shown here which will eliminate the side-to-side rocking of the spare tire and the deformation to the hitch over time. Without a Quiet Hitch, the rocking will slowly get worse.