here is my opinion
GBC dirt devil- ran them for a little while. honestly, they werent much better than a good stock tire.
Kenda Executioner- good in really thick mud but that was pretty much it. bumpy for trails, crappy in rocks and sand.
ITP Mud Lite- very versatile tire actually. wonderful in mud and were pretty good on the general trails.
Current tire that i run is the ITP TerraCross. radial tire, good wear. easily the best tire i have ever run. the amount of traction they get is superb. super grippy in rocks and wet conditions. however, if thick mud is your thing then i wouldnt run them cause they tend to clog. i don't do thick mud unless thats the only way through so that doesnt bother me.
My dad is running the Mud Lite XTR radial. this is great tire too and is great in the thick mud. If i had to buy a new tire, i would get the TerraCross, with the XTR a close second.