[rbmj]

I can't answer for the risks associated with using a new GCC. However, I can say that some of the standard library and language compliance benefits are very interesting and useful, particularly C++11 features. Additionally, should one discover any issues, the developers are much more likely to help you with a modern, developed version.

It is to both VxWorks' and GCC's benefit to keep compatibility current and not let it bitrot.

Again, a major motivating factor is to be able to get a native linux version. IN MY EXPERIENCE, the whole development process is smoother on linux, and not using the giant hulking behemoth that eclipse (and thus workbench) is makes development go much more quickly. CMake also does a better job of dependency tracking than the Makefiles that are generated by workbench or UCPP (no offense of course to the people who have been working on UCPP, which is an awesome project).