It works very well and has fewer bugs than 2.7.0 and 2.7.2.
To install it, you must remove every last trace of the previous
version. The different versions are designed to coexist, but
they do not.
At the very least, you should remove these things from /, /usr,
and /usr/local:
lib/gcc-lib bin/cpp bin/gcc bin/c++ bin/c++filt
bin/protoize bin/as bin/cc
I'm sure I missed many things. It is best to install the new version
right on top of the old version - in /usr or /usr/local as needed.
(this stuff really belongs in /usr though)
I'd also suggest upgradeing related things at the same time.
By that I mean libc, binutils, and ld.so. That might mean you
should wipe out /usr/include even. Be sure to do all the removals
before you start to add things back.