I've tried the CRC Synthetic Brake Grease on my caliper pins and all it does is harden up over time. I just redid the front brakes again and the pins would barely move. This, inturn, wears the pads unevenly. This time I am using the following stuff:
Toyota p/n: 08887-01206
About $8 / 100g tube.
Supposedly this is the factory stuff used/provided with brake caliper rebuild kits. It's pink in color.