The PIV is gonna be bigger, heavier, and slower with better storage and rough water abilities. The P4 is sometimes called the mini Puma. It is what I would choose as I would generally give up speed for storage and rough water ride and deck space. The PIV has a wider deck also I believe.
You might want to take a ride in a 198 or 202 Champion before you pull that trigger though. The Champ/Stratos feels much bigger (to me) than the Cat even though it's really not. 25 more ponies couldn't hurt your resale.
Hardcore Bass Apparel
There's One, Sterling