I think there are several benefits in using clang tools. You might find useful the Chandler Carruth's talk on Going Native on which he demoed some great tools that doesn't really have alternative on the gnu toolchain.
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...
Would you mind submitting a bug report (with a reproduction case, if you're able) to the Clang team or mailing list? IIRC, they have an automated test suite for performance and regression testing; I'm sure they would greatly appreciate you taking the time to submit a test case where clang is producing egregiously slow binaries.
I could try, but although the difference seems localized to a fairly small number of functions, I haven't been able to precisely identify why it's so slow (there's no single inner loop etc that's slow), and shrinking it to something minimal would be hard...
I think there are several benefits in using clang tools. You might find useful the Chandler Carruth's talk on Going Native on which he demoed some great tools that doesn't really have alternative on the gnu toolchain.
http://channel9.msdn.com/Events/GoingNative/2013/The-Care-an...