A few things to consider overall:
1. Must do Intern year (can do an EM intesive track)
2. Some programs are horrible (rotated at a site that anaesthesia was regularly called because the ED attendings couldn't get a tube, and no ultrasound whatsoever), some only take 2 residents a year (something can always be said for critical mass.) BUt then this also applies to a few ACGME programs.
3. Most programs are smaller and at lower volume/acuity hospitals. (I'd rather learn how to treat critical paitents than fill out EMTALA forms to ship them to a hospital that can.)
4. Your Board Certification is dependent on AOA MEMBERSHIP! forget to send in your dues and you are not certified. How is that for a captive audience.
On the plus side, when you graduate you have a year more than most EM graduates. And most hospitals want you to be board certified, period. Also, if you look at the match list, there are a ton of AOA EM positions open. And Some I would do in a minute.