If you buy an elec/hydraulic unit, please take my advice, and get a top of the line brake controller to drive it with -- I like the BrakeSmart, but the Jordan appears to be just as good. I don't beleive the Prodigy will work with the elec/hydraulic very well without some modification on the trailer end.
I converted from vac/hyd to elec/hyd on the same trailer, and was ready to convert back to vac/hyd due to proportioning issues, until I upgraded to a BrakeSmart Controller. I had very frustrating problems with a Tekonsha Voyager. That being said, if you're running roughly the same weight, it's not as bad. In my case I might pull into a place with a gross of 18,000 and pull out with a gross of 32,000... . so you can see the proportioning problems... .
--Chris