The only time I've bothered with using a rattle can of this stuff was in preparing a 1/9 scale Warriors figure that I had picked up off an e-Bay seller from the Far East. This was most likely a pirated re-cast because I have never encountered a casting from Warriors that was so filled with surface pitting as this kit. The only reason I used the rattle can was because of the size of the pieces. Using standard putty would have taken forever to cover all of that mess.
If I recall correctly, I sprayed three coats of the 500, wet sanding between each coat. Once all of the pits had been filled, I used a light coat of the 1000 product as a primer to sort of pull the surface together for a uniformed surface before proceeding to color coats.
The whole project was a nightmare and the Mr. Surfacer 500 was certainly something of a time saver. I haven't found a use for the rattle can version since.