Hi Jay-
Would there be advantages to enrolling in a purpose-built "Upset Recovery"
course instead of say, just popping over to the local FBO and scheduling a
hop in a Great Lakes or Decathlon to experience spins and spin recovery?

I have seen a noticeable difference between typical upset-recovery
courses and beginning aerobatic training.
The upset-recovery course should concentrate on specific scenarios that
could lead to unusual attitudes, such as a wake-turbulence encounter, a
skidding/tightening low-airspeed turn, loss of spatial orientation, etc.
It should provide exposure to unusual flight attitudes, opportunities
to experience the specific scenarios, and techniques for avoidance and
recovery. It should also include exposure to a good variety of spin
modes and techniques for spin recovery. It should talk about
transferring the skills you learn to the normal GA aircraft you fly most
of the time. You may never get to fly a loop in an upset-recovery course!
Basic aerobatics training, on the other hand, will be more aimed at
control of higher-performance aircraft used in aerobatic flying. It
should cover the basic aerobatic maneuvers, such as loops, rolls, spins,
hammerheads, and combinations of all those. It may also focus on
adjusting your system to the unusual sensations of higher-Gs and
sustained inverted flight, and helping you to build up your tolerance.
It should also cover techniques for recovering from typical botched
maneuvers, as well as a full series of upright and inverted spin recoveries.
Similarities between the two include the exposure to unusual attitides,
the knowledge gained on how to recover from unusual attitudes, and the
spin training. But there is enough different between the two types of
training to make your question worth thinking about. If you are really
after only a confidence-building and skill-building experience for your
future straight-and-level flying (or anre not sure if you want to get
into aerobatics), then I think the upset course is better. But if
you're sure you're really interested in getting into aerobatics, the
basic aerobatics course is better.
Either one will be a big ol' boatload if fun! And there are lots of
places close to you to go for this training. FCI has an operation right
there in Chandler if I'm not mistaken, Budd Davission at Scottsdale can
take you up in his Pitts, and Sonny Weller is just up the highway in
Derr Valley. Have fun!

Tom P.