Anyone have experience with the classes taught by S&W? I'm thinking about taking either their Handgun Technique or Defensive Handgun Fundamentals class in the next few months.

I've taken some classes there over the last year or two.  Have taken Handgun Technique, which is sort of a pre-requisite for some of their other classes, Concealed Carry, Shotgun 1, and CQ Handgun 1 and 2.  None of the classes are bullseye or target oriented, but more self defense oriented.

Handgun Technique covers draw and recovery from/to holster, pivots, turns and builds on from that.

The Concealed Carry 2 day class was a lot of fun.  Reviews what you learned in HT, then covers a lot more fire and movement, cover and concealment, draw from concealed holster,and even gets into some scenario based shooting under stress where some classmates drew their pistol and blasted the first targets (good guys) they came to instead of looking for threats.  Ends with discussion of the legal and moral implications of carrying a weapon.  Highly recommended.

Close Quarters Handgun 1 and 2 are like they sound, focused on fast point blank defensive shooting.  Assumes you already know how to draw the weapon, pivot, etc.

My other formal training has been pretty limited, but I've enjoyed the classes there and would recommend at least trying one if you live in the area.  FWIW, in some of my classes, other students have come from as far as Penssylvania to attend, also others from NY, CT and VT.

Any suggestions on what kind of equipment is needed, and how much ammo to bring? Currently all I've got is a S&W 908, the two holsters it came with, and a cheap generic IWB holster. Would that be sufficient for one of those classes?

You can rent pistols from the pro shop at the range and buy ammo there too if you need it.  If you're going to do that best to include a note with your registration.  I'm not familiar with the 908, but in the classes I've taken I've used full sized and compact M&Ps, others have also used M&Ps, Glocks, 1911s, S&W Sigmas, Beretta 92, even a Walther 380.  There have been a few revolver shooters.  I'd recommend minimum 2 spare magazines (most had more, but you will have time to reload) and for revolvers you'll definitely need speed loaders or speed strips.  S&W usually posts a list of minimum class equipment requirements on the website.

You really need a good quality leather belt and good quality holster.  Since you'll be drawing/re-holstering frequently, the people with top snap holsters were at a distinct disadvantage.  I used a Serpa holster one class, which takes some getting used to, and when other people tried my holster they had lots of difficulties.  Other classes I used a Desantis leather holster (without top snap).  Another important consideration in the holster is will it stay open enough to easily get the muzzle in to reholster?  People with cheap or worn out leather holsters had more problems, and people with kydex/synthetic holsters had a slight advantage.

All of the classes were a lot of fun, and I think most all of us felt we improved our skills.