If it's REAL muddy cleats won't do a lick of good. They get caked up just liks boot treads. Where cleats really excel is on damp, not saturated, soil.
But if you insist on cleats I suggest ones with screw in spikes rather than molded spikes. The metal screw-ins last longer but are very slick when walking on wood, tile, smooth concrete, or other such surfaces. The plastic/polymer work just as well in mud and aren't as slick on hard surfaces, they just wear out faster. Buy plastic spikes and keep plenty of extras.