Gavin.
I have a wood epoxy BR - No. 12 since 2008 and am extremely pleased with her.
Although there wasn't an option of a GRP BR when I bought her, I think I would still have gone for the WE. As Julian says, maintenance and repairing the odd little (!) scratch is very easy. This winter I am planning to strip her down, sand and repaint her - not that there is any deterioration, after 5 years she just needs a little tidy up. She should then look like new, you try doing that with a GRP boat!
Unless you have professional skills, gel coat repairs are always quite noticeable. My boat too has the option of a striped mahogany decking, which to me looks far better than the GRP 'plasticky' look...
Moving her around on her trailer on the driveway at home is a lot easier than the GRP version, which is quite important for me - I live on the side of a hill.
I have quite a lot of experience in sailing both the WE and GRP and I couldn't really say one is better than the other, the GRP is heavier so maybe slightly more stable, but I will stick my neck out and say my WE boat maybe slightly faster..!
The WE is more expensive than the GRP versions and the waiting would be longer if you were buying new.
Whatever you choose, you will just love the BR, there is nothing else quite like it out there.
Good luck!
Andy BR12 'Psalter'