I would recommend using something with at the very least a 12 to 15 mil finished thickness. Anything less than that will not fill even minor pitting.
I've used U-Coat-It, Epoxy-Coat, Rustoleum, Quikcrete, Griots and most recently Wolverine. My final thickness from the Wolverine system was 27 mils. It was definitely the best quality of anything I've used.