Can you explain the basic training differences between these organizations for tech training?
Standards and Procedures:
UTD
GUE
UTD's tech progression is broken up into smaller steps.
UTD T1 = 25/25 bottom mix with oxygen deco gas, max depth of 130 (PO2 of 1.2ish). Check the standards for max deco time.
GUE T1 = 21/35 or 18/35 bottom mix with EAN50 or Oxygen deco gas (but not both). I believe in their latest standards they use PO2 rather than depth as the limit, and it's probably 1.2.
UTD T2 = 21/35 bottom mix with EAN50 deco gas, max depth of about 160 (PO2 of 1.2ish). Check the standards for max deco time. UTD also teaches use of a stage bottle in addition to the deco bottle. At this level it isn't used to extend bottom time, but rather to allow two dives on one set of doubles while maintaining rock bottom.
GUE T1 and UTD T2 are roughly equivalent. GUE offers a T1+ where stage bottles are introduced. UTD offers T2 Gold where the second bottle can contain a different deco gas, but with the caveat that it isn't to be used to do more aggressive dives (i.e. no 2:1 decompression dives on a UTD T2 Gold cert).
UTD Trimix 1 = 18/45 bottom gas with EAN50 and Oxygen deco gases.
UTD Trimix 2 = hypoxic trimix with multiple bottles and leash work, with some max depth.
GUE Tech 2 and UTD Trimix 2 are roughly equivalent.
GUE Tech 3 is basically irrelevant (in practice, anyway). UTD offers Trimix 2 Gold which eliminates the depth limit.
A fundamental difference is how decompression is covered. UTD teaches Ratio Decompression as the primary means to plan dives. GUE teaches desktop software as the primary means to plan dives, with Ratio Decompression as a backup. [I believe this is still true]
Also, I know there aren't any GUE instructors in AZ. Are there any UTD instructors in the state?
North American UTD instructors (none in AZ):
http://www.unifiedteamdiving.com/page/usa-mexico-canada-based-utd
What classes does UTD offer for tech and how long does each one take?
How long? That's an open-ended question. It depends on the instructor and the student.