Before pondering which of these programs, if any, to support, it's worth thinking for a moment on whether certification is useful at all. There is some controversy around this issue, to put it mildly. Opponents of certification fear a money-grabbing obstacle course that must be passed in order to work in this field. Or they suspect an attempt to set up a guild system intended to limit the number of certified engineers, and thus keep salaries up. Those concerns are valid, but there do remain some useful aspects of certification.
Certification can also provide both a goal for and a means of evaluating training programs.
Insofar as the certification exam is a meaningful test of Linux ability, a training program that enables people to pass the exam is achieving something useful. That means independence from any one vendor, an open, transparent, and accountable development and management structure, and as much information available as possible. Applying those criteria leave the Linux Institute and Linuxcertification.org as the clear top candidates. The two groups currently appear to be very much in competition with each other. It may be that the community can be well served by competing certification groups, but it is not clear that this is the case.