As an 1yr AEGD grad I would HIGHLY recommend doing this. As a matter of fact, I'm really glad the Army forces us to apply. The AEGDs are designed to "calibrate" new dentists into the being more comfortable with more advanced dental procedures and (most importantly) treatment planning. The experience will vary depending on the staff and that is always changing (so there's no one place that's "always good" or "always bad" - remember everyone usually moves every 3 yrs in the military, so the good/crappy mentor will eventually move on). Speaking of staff, the mentors in Army programs (can't speak for other services) tend to be young, full of energy and up to date on the latest and greatest. Plus, they are NOT some "gun for hire" or "superstar doing you a favor" like what you would find in many civilian programs.
To be blunt, with the wave of new dental schools opening and the quality of dental education being so uneven, and the fact that (if you were like me) many students focus on "getting their requirements done" , there is a MASSIVE difference between an AEGD grad and someone right out of dental school (some would say its the equivalent of 5 yrs of experience squeezed into a single year).
Just do it!!!