C is much better for students. It is a main stream language (probably the most common one) while PBASIC is a stripped down version of BASIC made by Parrallax. Of the 6 programming HS students on the team, 4 had already programmed in C (or C++) in school so I didn't have to teach them the language.
No student who has ever entered our program had ever heard of PBASIC before. Only one engineer on the team ever programmed in it before (he was a pro but he really wanted to use C like in the Atmel processors he uses at work). After he left in 2002, I had to teach everyone (students and a couple new mentors) PBASIC, because I had done a little programming in my rookie year. Some people had QBASIC or Visual BASIC before so most of my time was spent teaching limitations of the code (no function calls or signed math) and its inefficient syntax (more goto statements then I ever want to see again). It should be easier for teams to find mentors with C experience since it is such a common language.
Along with the increased power of C comes increased responsibly. There are many new ways to shoot yourself in the foot. Projects contain over a dozen files (and include many more) instead of 1-6 (depending on how many 2K banks you used). The biggest problem with C this year is the MPLAB complier and all of its bugs (yes I know I can use something else but that is not easy when you have a big programming team)
Overall programming in C is a more valuable learning experience for the students because they are likely to use it again in college and their careers. C will probably continue to be widely used in the future for low level applications. Basically all new languages are object-oriented or intended for web use. None of these languages are appropriate for a procedure oriented system like a robot. C is a superior language to PBASIC so FIRST should keep it. C is going to be around for a long time, so learn to like it, or start building a PBASIC to C converter.
(I think Mike Soukup built a C to PBASIC converter, maybe it will work in reverse
).