At $20 shipped this is an okay deal if you need a Model M parts keyboard. If anyone bids against you at all, I'd say let them have it.
Model M:
PS2 + "untested" + even a trace amount of scepticism = Actually tested and found to be dead. Plus missing caps.
Mini AT:
AT + "untested" = Seller didn't think it was worth the $2 to buy a converter to test it. I would be wary.
Saitek:
I picked up that exact model a while back (new) for five bucks shipped as a throwaround/backup. Used it belongs in a dollar bin.