It's really awesome. Before you switch to Go, you should consider it. People understand how it works right? The preprocessor for each file is run (i.e., gcc -E), and it's inserted into a hashtable (key: the checksum of the preprocessor output and the .cpp or .c file, value: the .o file). If the preprocessor output and the .c or .cpp haven't changed (checksums match), instead of recompiling the .o file, the stored .o file (usually in ~/.ccache) is just copied.

It's actually really hard to make a compiler that's faster than that (amortized cost of nothing). And it's not the same as precompiled headers. In fact, it's about as similar to precompiled headers as Windows is to Linux. I.e., one is based on small parts of the pipeline that are precise and always work if you know what you're doing, but are poorly documented -- '5 to 10 times as fast' as mentioned on the website is just incorrect).

Anyway, Go looks awesome. But I wouldn't use it only because of compilation time.