I am in the DL program at SES. Since I have not attended any other seminaries, it's hard for me to compare the rigor of the programs. And I haven't done the extensive comparison from Rhetorcian's list, but I do know that:
--Most of the prof's have taught at other recognized, regionally-accredited seminaries and universities, such as Dallas.
--The doctorates are not in-bred. If nothing else, it's because it's a relatively new seminary (about 13 years old), and they didn't have a doctroate program in the beginning. So I think ther reason you don't hear more about SES is that it's just not been around as long as other seminaries.
--There is a good mix of educational/theological persuasions. For what it's worth, Dr. Geisler is a baptist, although now he pastors the church that meets at the seminary.
--From my personal experience, I'd say it's a rigorous program. Every class has required me to read about 600 to 1200 pages, and it takes me a minimum of about 20 hours a week per class to do a good job.
--The distance learning part of SES involves DVD's of the class lectures, so you're seeing the exact same thing as the people on site.
--The areas that set SES apart from other seminaries is the empasis on apologetics and the philosophical foundations of christian and non-christian thought. You won't find those emphasis anywhere else that I know of.
--The profs names are the ones you'll recognize from the apologetics shelf at your seminary library.
--SES offers regular on-campus semester classes, as well as one-week "modules" that are open to externals and on-campus folks.