Looked at something like this, but going with the Bender monoshock for the Warrior.
Way I look at it, the Bender is just over $1k. That includes a new Penske shock. The shocks on the used AC probably need a rebuild at best, or replacement at worst. That's probably going to cost over $500 right there for semi-decent new shocks, over $800 for basic Penske type quality, and then you still have the cost of the suspension, which is used.
Supposedly the Bender is on a par with the '05 RX 1, which most of the magazines seem to think is as good as any other rear suspension out there.
What attracts me as well to the Bender, is the easy, toolless suspension changes to rebound and damping.
I may upgrade to the Penske remote reservoir with separate compression, rebound and preload, but this is an extra $500. Not surprising as they quoted me over $1K for a similar shock for my motorcycle.