@Dr Herbie: To give you some numbers, on a single HDD, the compile times are about 30min. With an SSD, the compile times are about 13min, on a RAID-0 SSD array it's about 9min. For this project, every single minute saved in build time is absolutely amazing and totally worth it.
This project is pretty big, and is entirely C and C++.
I imagine for C# the net benefits are going to be less significant.