One thing Nelson HAS to do is keep from getting sued so he supplies a UL approved pc and it's a good one. I'm not surprised you found it better than the ones you bought on ebay.
As to the best....that's up to you to find out. For my 100.5's and 30.5, I am using DH Labs Power Plus (ballpark $300). It's not in my DNA to spend more than a few hundred on a pc.
I also tried Liz's Pangea 9's on the XA.5's with no complaints. You mentioned "punching power". Those are 7 gauge compared to the 14 you are using now. Might give you more punch.
