The electric booster has been used on 88 t birds that were turbo, GM had them for a few years as another person posted, and yes , they were very unreliable.
Ford has used them as a safety backup brake booster for the f 600 (and up) since back in the day.It had hydro boost w a electro boost piggybacked to it.pretty cool.
The turbo t bird ones were pretty reliable actually and were implemented with the ABS which you can simply not use if desired.
I would pesonally go for the hydro boost setup. They are very reliable .As they are pretty common, parts are readily available too.
It pays to shop around . someone has to be making these with chrome and better outwardly apearance for us hot rod guys.