I ran a Sparton Sprint, Super and Beast with these shoes. Top 7% in all events. I'm not the fasted but im competitive and I know what's needed for shoes!! Grip is great in mud!!! and no sand or debris gets in your shoe!! Zero!!! Best shoe ive ever used for both of those.
 But,,,,,These are terrible on hard surfaces. Way to hard of a plastic!! on rocks you can get killed, you slide across with no grip at all! the shoe is also terrible on your feet its like running on cement. I even put inserts in but they fit so tight you cant really put anything in that will help.
Now they did hold up great so that amazing. I hosed them off and they look pretty new.

If your ok pounding your joints and you know its a earthy/wet course these are the bad boys you want other than that stay clear because i needed a couple of easy days after to heal