My dad decided to snag them and use them on his Bayliner (he's retrofitting his tongue to allow for hydraulic and then running the brakes). Sorry, I should have updated that these got used up.
What ended up happening w/ my trailer is I had the disk brakes pulled, everything from the blue wire to the 5-pin adapter all the way to the disk brakes and it was put in a box (so all the hydraulic lines, the solenoid, the hydraulic actuator, the brakes and the pads).
I had the trailer mfg (metalcraft trailers) put drum brakes on the rear axle with electric brakes. They had to put in a brakeaway switch. All in all, they charged me 400$ to do this and they had it done in about 3 hours. They took a piece of tube steel and put it up inside the tongue forcing the hydraulic sliding hitch point to stay put and then they spot welded it in place (just in case I ever wanted to use hydraulic brakes again). So now when I stop and start there is no clunk noise. I love electric brakes, even if they are drum brakes and I submerge them... I had electric brakes on my last boat too and they never had an issue.
from the looks of it, this would be a really easy upgrade to do on your own.
breakaway switch for legal reasons:
http://www.etrailer.com/faq-trailer-breakaway-kit-installation.aspx
Electric drum brakes, and about 30' of copper wire is all you need. Replace your disk brakes + pads for drum on your axle, pull all the hydraulic lines, then you just run 12V to the electric trailer brake control pin (out of your 7-pin, requires an electric brake installed in the tow vehicle), and 1 line goes to ground, the other goes to the 12V connector. ... Since I didn't do the install myself I don't have the exact parts list. I was going to do it myself but life got in the way.
Probably the best thing that electric brakes have over hydraulic brakes is the brake release when you're not braking. Helps for backing up, but even more so helps for taking off from a stop. That little "thud" that the hydraulic tongue does when you start accelerating REALLY takes it out of your tow vehicle's low end torque. Everyone has tricks for dealing with that, but I quite enjoy not having to.