I have owned both a FF 182 and currently a FRP and they're different beasties really. From experience:
182:
+Better daily drive (FRP suspension is HARD)
+Quicker (in a more civilised way) on the straights. Round corners it is a different story - FRPs corner like race cars - nice controllable lift off oversteer etc, but no surprises
-Common - have you seen a FRP??
-Similar build 'quality'
+182s are better equipped
+Cheap parts as high volume car
FRP:
+(Subjective) but looks amazing
+Gets looks
+Sounds incredible (Pop pop pop BANG)
+Feels 'special'
+Rare
+Good power from a 1.7 (155bhp)
+Best brakes of any road car I've driven - the Alcons are phenomenal with ZERO fade
+Retain value
-Needs more power (being fussy) for straights
-Cost of ownership is high - brake servicing / parts etc
-You get paranoid about someone dinging those arches
-Need specialist care from someone who knows them
I'm actually selling my FRP / looking to swap it purely because I need something bigger / more 'daily driver'.
The cars are awesome - anyone who owns one or has been in one falls in love with them. Shame so many get broken for parts and / or written off