I've only paddled the Fenn Elite Double and the V10 Double in recent years. In the Fenn I was in the back, but in the V10 I'm in the front - I own a glass layup V10 Double that we're going to do the Cape Point Challenge in.
It's difficult to compare the speeds of the boats but I can say that the V10 is easier to remount than the Fenn! The V10 has wider cockpits with lower rails. Previously we battled to remount the Fenn in Fish Hoek bay at the end of a downwind - and I think just about the first time we paddled the V10 we came out 2km out to sea at the lighthouse... I thought we were going to have some admin, but the boat proved exceptionally easy to remount.
I think the V10 is slightly more stable than the Fenn Elite double.
Rob
Currently Epic V10 Elite, Epic V10 Double.
Previously: Swordfish S, Evo II, Carbonology Zest, Fenn Swordfish, Epic V10, Fenn Elite, Red7 Surf70 Pro, Epic V10 Sport, Genius Blu, Kayak Centre Zeplin, Fenn Mako6, Custom Kayaks ICON, Brian's Kayaks Molokai, Brian's Kayaks Wedge and several others...