Clang certainly has its advantages (the faster compile times are very nice), but for a typical user that just wants to compile stuff, there's really nothing huge—and as always they need to balanced against the disadvantages. In general it's often a wash, and you may as well just use whatever comes with your system or whatever your friends use...

For me, the killer is typically optimization: e.g. for a CPU-intensive app I work on, gcc generates a binary that is twice as fast as what clang generates (this has been true for ages and across many compiler versions). I can live with slightly pokey compiles, but having my program take one week to execute instead of two is pretty compelling...