I find that Cavallo boots are GREAT for round, wide feet. They tend to slip more on narrow, boxy feet.
Pros: VERY easy off/on , easy to clean, wonderful drainage holes if you cross water a lot is a plus, and you can still use easycare pads in them, just cut them differently (if you ever used the pads for any reason). Durable. No traction problems on terrain.
Cons: since they come above the hairline, there IS more chance for rubbing, but my clients that have them, use the pastern wraps and swear that eliminates the problem and these gals are serious trail riders in all terrain. Also, they look a bit clunky and twist if they don't fit.
The Epics/bares are better for more oval/boxy feet, in my experience. Boas are made by the same company, and are more similar to cavallos in style, but the shape is better for narrower feet, as well, plus the cables can snap, and there is a cap that can pop off and get lost pretty easy. Still a good boot for foundered horses, and if you don't hit the rough country.