Yes, it should be able to be used with any wall wart. I'm pretty sure they all have about the same power output.
I've been testing the RPT-1 and it works well. I think this is a good solution for guys operating on someone else's layout, a club layout, or Freemo. If you're concerned about signal being lost, or are in a saturated area (show), then throwing a couple of these things around the space is simple and works great. Either put them in a wall wart or in a cell phone battery pack.
Or if you want to increase the signal on your own layout without adding a much more expensive PWR-56, these are a simple solution.
-Kevin