For those wanting an introduction to the skills and gear used in DIR diving, UTD offers Essentials and GUE has its Primer course. Both would be a good starting point for those with a passing curiosity of DIR (or its skill set), but not wanting too much of a heavy dose concerning team diving or a heavy emphasis on situational awareness.
For the recreational diver who is looking for a solid introduction to DIR, plus a nitrox certification, UTD Rec 2 and GUE Fundamentals both offer a good foundation.
For those considering a transition to "technical" diving (i.e. >NDL, >130'), UTD Intro to Tech or GUE Fundamentals (with tech endorsement) would be good options. They cover roughly the same skill set. The UTD class has you carrying a deco bottle for practice, but I don't think it's necessary (we lugged an AL40 around for only two weekends before doing T1, it wasn't an issue). GUE is stated as max 4:1 student to instructor ratio, while UTD is 6:1. Fundamentals is a prerequisite for any further GUE training, while UTD has no such limitations (meaning you could take UTD Tech 1 having done GUE Fundamentals, but you can't do GUE Tech 1 having done UTD Intro to Tech).
Because of this last point, it might be worth figuring out if GUE Tech 1 or UTD Tech 1 is a more likely goal.
Other huge factors that might play a role in your decision include: do you have a local GUE or UTD instructor, are there any local GUE or UTD trained divers, and will you be traveling to areas with GUE or UTD divers.