If you want a maintenance-free brick floor, don't put anything on it that will require maintenance. As Nancy says, brick is porous and needs to breath. If you seal up the one side that breathes, well, moisture may build up inside the brick and 'push' any type of stain or sealer right out! You've probably experienced this already with having to remove what you put down before.
My best to ya and hope this helps. If you have any more ???'s on this, do post up.