Regarding ramp vs. step-up, a lot depends on the horse. I have known horses who would walk up to the step, and just refuse to go further, and some who went in readily, but got very nervous about backing off into air. Mine prefer to have a ramp, but it would be really great to have a trailer that could be either one. I also think a gooseneck is more stable, but I am neurotic about trailering my horses. Whichever trailer you choose, be very, very certain that your tow vehicle is up to the job. The only SUV’s I know of that can do it are the Chevy Suburban and the Ford Expedition, which are really trucks in disguise. GMC may make something equivalent to the Suburban.
It is never the horse's fault