You could pretty much read for a couple days straight on the topic if you search around. You'll pretty much find a large group supporting both.

Personally, I highly highly highly prefer infloor cleaning, and the PV3 is a great product. I do suggest using either an open slot style drain or the MDX R3 drain with an infloor system. Much better cleaning than standards drains.

I will say that a $5k upgrade sounds like you're being gouged unless you have a very large pool/spa or your plumbing run is substantially lengthy.

Best of luck in your decision!