I have never tried a reverse load, they seem to be popular with the barrel racers here in Texas. I have used a cattle trailer of some sort most my life but recently aquired a Logan 3 horse slant. My horses started hesitating getting in. I took the dividers out and now they hop in again.
I never had a ramp trailer but assisted a few folks with loading their horses into one at shows. They all had ramps. I don't think horses like them if not trained to use one.
I have used a stock box or cattle racks and had horses jump flat footed into one to load up or out, never had a problem whether it be the first time ever or the 100th.
I DON'T LEAD 'EM AND FEED 'EM, I RIDE 'EM AND SLIDE 'EM.