Before you further consider a PF/2 system, I suggest you contact Crane and find out how much longer they'll be using that particular system. I would also ask about technical support and the cost and availability of replacement parts. Last year Eljer moved away from PF/2 and now uses Flushmate's system. It wouldn't surprise me if Crane did the same.
My experience has been that PF/2 parts are either unavailable or extremely over-priced which is unfortunate because the system is prone to failure. It's not a case of "if", but of "when".
Extreme water conditions will speed the deterioration of the Flushmate duckbill valve but it's an easy fix and parts are readily available (usually for free) from Flushmate. If you enjoy the effectiveness of pressure-assist fixtures, Flushmate is the only way to go.
For my money, pressure-assist is the only choice, but like anything else, consider your options and make your decision based on what's right for you.