I like Easyboot Epics the very best out of the ones I've tried. I've put lots and lots of mileage on them and have worn out a couple of sets. I occasionally have to replace a cable or patch a "gaiter" (the thing that wraps around the pastern) but really I have been very happy with them.
Others I have tried:
Old Macs (the original style). I bought them from Easycare and the soles started cracking after only two rides in the rocks (I only boot for rocky rides). So I sent them back and got them replaced with Epics.
Easyboot Bare- I thought they were difficult to get on and off, so I replaced the bungee system with cables, essentially turning them into Epics. I also think they have less traction than the Epics and I feel like my horse is more likely to slide in loose rocks.
Easyboot Gloves- I've tried the "fit kit" and they didn't fit my horse's front hooves well at all, so I returned the fit kit and bought Epics instead. My horse has wide feet, and he wears a breakover pattern in the toes. The gloves are made for a round toe, not one with a squarish breakover like my Mustang.
So yeah, I like the Epics!
I've never tried the Cavallos Simple boots, but they looks A LOT like Old Macs, and after trying Old Macs, I figure I would break them, lol!
If you haven't already been to EasyCare's website, go there. They make nearly every boot available on the market, so there is info and comparisons of all the boots there.
I usually only boot the fronts on my horses, and I usually only boot for riding in rocks. But when I do use them, they are a Godsend for barefoot horses.