I installed electric brakes and, if you have the flange on your axle, they really are a piece of cake. An afternoon's job, if that. Just make sure you get a good proportional brake controller (e.g., Tekonsha P3) for your tow vehicle and you'll be good to go.
My trailer only had flanges on the front axle. I had to weld flanges on the rear axle but it wasn't all that hard once I fab'ed a jig.
After flanges, I REMOVED the entire surge brake system and installed Dexter Nev-R-Adjust electrics.
I have a 2005 F-350 Super Duty with the built in Ford OEM electric brake controller and everything not only works flawlessly, but it works FAR better than the POS surge brakes the trailer came with new.
If you do not have flanges on your axles (and you can't weld your own) you'll need new axles that have the flanges. I bought 4 complete brake assemblies PLUS drums, seals and bearings for about $150 per axle.
If you're going to do salt water, you should get disc brakes and an electric/hydraulic pump to operate them (only certain pump units work with the earlier Ford EBC system)
I'll NEVER go back to "surge" brakes!
Regards,
Rick