Effects of powder coating?

We have ve been offered a good deal on powder coating our aluminum, but I was concerned that it might affect friction with moving parts or add weight or thickness to a significant degree. Does anyone with powder coating experience know the actual effects of powder coating aluminum for vex robots?

We have never powder coated or painted our parts, but we did have some metal donated to us and some of the aluminum as well as the steel had been either painted or powder coated on anodized. I am not sure which process was used but we have experienced no reduction in performance.

Here is an article that goes into some of the processes. It would seem that the safest bet would be anodizing the aluminum.