@Okie,

For the primary stats: STR VIT DEX INT MND PIE. No soft cap has been discovered by folks. The full benefit of stats appears to continue even with a full set of the highest stat gear, then stat allocating towards the stat, eating food (if applicable to the stat), receiving the party stat buff, and drinking an HQ stat boosting potions. If there is a cap, it's beyond the reach of the resources currently in the game.

For the secondary stat ACC, this appears to be depend on the class. As someone earlier in the thread said, around 440 ACC appears to give you a 100% hit rate for casters and around 480 ACC for melee to reach 100% hit rate.

Now Items? Items have stat caps.