There are some good reasons to try the Sun Studio Compiler Suite. One of them is a better performance of the resulting code than with GCC . The BestPerf blog reports about their findings in “Free Compiler Wins Nehalem Race by 2x
Not the Free Compiler That You Thought, No, This Other One.”:
The freely available Sun Studio 12 Update 1 compiler on OpenSolaris provides more than double the performance of GCC V4.4 on SuSE Linux, as measured by SPECfp_base2006. If compilation is restricted to avoid using autoparallelization, Sun Studio still wins by 38% (base to base), or by more than 25% (Studio base vs. GCC peak).
From my point of view the real point of GCC isn´t performance … it is his ubiquity on almost every platform. But for performance you should opt for alternatives.