Well, it is installed and short story: it probably wasn't worth the time and money. That said, this would be an excellent and economic replacement for a worn-out pump, if they happen to be available when you need one.
Longer version: I've been checking the WHP website periodically and the other day things changed from 80 on order, 0 in stock to 63 on order, 1 in stock. So I snapped it up. They shipped it by DHL and it arrived from England in 3 or 4 days.
Before installing, I did some loader work moving snow piles to warm up the fluid. Then I checked the cycle time: 4 cycles of the lift arms from bottom to top and back down again took 63 seconds -- just a hair under 16 seconds per cycle. After installation the same 4 cycles took 51 seconds, or about 13 seconds per cycle. Better, yes, but less than 20% faster -- hardly the twice-as-fast I was hoping for by swapping in a 6 gpm pump for the stock 3 gpm unit.
Installation was reasonably straight-forward, except for the one nut at the top outboard corner. That one was a mother and required some customization of a 12mm wrench with a torch and grinder.
The plumbing outlets were fairly close to the stock location. The hard-piped outlet was 4mm further from the flange and the inlet is on rubber hoses anyway so the deviation was easily handled. For the outlet, I loosened the bolt securing the hydraulic block to the engine about 1/4", connected the banjo to the pump, then tightened the hydraulic block back up to draw the pipe into place.
Here's some pics comparing the original pump with its bigger replacement:
And one of the new pump installed: