(Correct me if this belongs in meta) For undergraduate students considering a career using GIS but who will not be graduating with a degree in it, is it a worthwhile investment of time to pursue a GIS certificate/certification? If so, what criteria are important to consider when selecting a test/program?
A GIS certificate may help refine your GIS skills, however there is more to selling yourself then just certificates.
Employers want to know how have you contributed to the GIS discipline, or what project wise experience do you have leveraging GIS.
Surround yourself with GIS professionals (network). Join a local user group, or present at a conference.
These are very important to consider when competing against the pool of new grads. For certificate programs, search for a program that fits your goals. Some programs go over the basic user functions of GIS. Others are more focused on development and programming.