I would buy the 9000. I've had an 800B and parts if any are expensive. I own 3 PW's 900, Platinum and 800+. Any of those 3 would be better than an 800B...
I've run both. I started with an 8567 grabber and then a PW 800+ I prefer the 800+ hands down. Nothing really 'wrong' with the MEC, I just prefer the PW and I would never consider switching back. Partially because I like the ability to swap out gauges. I did not have to buy 4 separate machines, and the PW makes it easy to swap. It used to be the breakeven point from an expense standpoint was about 3 gauges - I have not checked recently. There is more to it than that for me - I prefer the built like a tank construction of the PW over the lighter, stamped construction of the MEC. Thats more of a personal preference.