Yesh. I think that's rather extreme. gcc has been working very well for me on my sparc machines. The only problem as far as perl goes, is that perl will need to be compiled with gcc in order for binary modules (also compiled with gcc) to link in.
Sun's compiler is optimised for sparc processors, and can compile 64bit elf binaries, the stable gcc compiles 32 bit and may produce less efficient binaries. I can't say how much performance would be gained or lost either way; I haven't done any benchmarking.
Perhaps some other monks have done some testing...
