I have 2 FNP40s, both are very accurate.
$422 with 3 mags is a good price; FNP40 prices jumped to the $500+/- level when the NIB supply started to diminish earlier this year and the FNX and FNS were in the upper $500 to $600 range. Nice to see some good deals out there.
The FNP line has been out of production since 2010 and I have read that not all FNP9 parts are being made, so some guns returned to FN under warranty have been replaced with FNX models. That is in 9mm, though, and I haven't seen that on .40s.
Let us know what you choose. I'm holding on to my FNPs.