SCO publishes updated information for developers at the Developer's Home Page (http://www.sco.com/developer); you should check this page frequently for updated information, new tricks, hotlinks to important news groups, and so forth. Anyone who is developing software for SCO systems is encouraged to join the SCO Developer's Program. The online registration is free.
The Usenet comp.unix.sco.programmer newsgroup is also a good place to read about the different development systems and to ask questions about which is the right one for you to use.
The following discussion references "performance". Here, this refers to the effect a compiler has on an application's run-time performance, where smaller generated code size and/or faster application execution time means better performance. Statements made here about one compiler having better performance than another are based on careful observations from running of industry-standard benchmarks. However, for any particular application, results may vary. If your application is performance-sensitive, you are advised to measure the difference in compilers for your specific program and applications.