Hmm... tough question. "Sand mix" is tough to describe seeing how it can mean almost anything. I'd say the biggest difference is the depth of the sand mix.
These are the footings I've ridden in:
Pros: dries quickly, easy to work, not to expensive, can dry out quickly, a well worked arena will generally be good for joints/feet unless it's too deep
Cons: will need watering, can be dusty (or very dusty, depending on the climate), can get deep easily (leading to joint strain or injury), doesn't dry as quickly as all weather footing
Pros: looks nice, no dust
Cons: can be hard or slick, certain disciplines will need studs on shoes for traction, can't take too much traffic, needs to be watered
All weather footing (bits of shredded rubber/tires mixed in)
Pros: feels great, doesn't flood, not dusty, great for joints/feet
Cons: extremely expensive
As far as falling off goes, I've fortunately only fallen off at home, which is a sand mix.