Brute Strength Gym here in Norfolk has about every implement known, including the Prowler II from Elite FTS. This thing has become an every single visit item for me along with the wheelbarrow

. 30 yards on the high holds and then 30 yards back on the low holds is definitely a party, not one with tea and crumpets but some kind of party surely. At the end of the third round trip, strange things happen not the least of which is definitely being VERY warmed up.
The back of their gym is a 40 yard concrete track, and the Prowler II is pushed up and down the concrete surely at least a hundred times a week. I personally contribute 10-20 trips depending on the week. It is holding up in a grand fashion so far, and they even take it out on the asphalt in the summer when the high school football kids use it. So yea, I would say it holds up very well.
In any event new feet can easily be welded onto it.
I like the wood foot idea for asphalt.