I have built three hollow timber boards over the years. Have a look in my gallery for a couple of photos or I have posted a few on here in the build your own thread.
www.seabreeze.com.au/forums/Surfing/Shortboards/Home-build-thread/Yes they are heavier than a standard board by a couple of kilos, i havent found much difference in paddling my 6'6" fish into waves over paddling a 7'2" hybrid into waves, rocker, width and bottom shape all play more important roles than volume.
I am bias but I think it surfs great on the waves its designed for, people that have had a good on it also comment how well it rides. The weight of the woodie disapears on the wave, the only time i feel it is in the swing weight up front. So it might be a little slower to snap of the top of a floater. But having said that the 6'6" fish I built is a traditional steve liz shape right down to the two ply kegs on it so shape plays a part in that as well.
I luv riding this board and even better to ride something you have built with your own hands as well.
cheers