JoffyH, what an excellent post. I don't think you've been sucked in by the marketting, I think you've made an educated decision which is right for you. The only thing i would argue with is that the OAA sims are NOT 737-400 sims. They are based around a 737-400 but are not a "737-400 simulator" which is an important difference. Other than that you are pretty much spot on.
I stand by my original coments that oaa is a very good (but expensive) option for integrated training, and perhaps not such a good one for modular, but as captin rossco rightly pointed out, it's different strokes for different folks. I am (on the whole) happy with my groundschool at oaa, although i think the books could and should be more concise and exam relevent rather than trying to teach us to fly to the moon one handed and blindfolded!!
I also think that it is important for past and current students at all colleges to come onto forums like pprune and "tell it like it is"...good and bad so future students can make up their own minds with objective comments as no fto is going to put "well actually we're a bit crap" on their websites!!!!