What kind of aircraft are used by the contractors delivering IFS? 172's? Fuel injected or carbureted motors? Garmin G1000 instruments or steam gauges?
I just finished IFS at Skywarrior, and all of my flights were in Cessna 172s, all of which were probably 20+ years old. All had carburetors and steam gauges. Some flight schools use Pipers from what I hear though. All but two of the instructors at Skywarrior were young guys trying to build up hours for the Airlines.
Everybody does IFS, including SNFOs, Marine & CG SNAs, and Foreign Nationals (mostly Saudi it seems like). The USN/USMC program is between 13-15 hours and the Coast Guard program is around 25 hours. The CG requires their SNAs to do night flying and cross country's in IFS.
I don't really think they make the flight school decision with any regard to putting you near where you live. All Marines go to Lightning in Foley, and all Coast Guard goes to Skywarrior at PNS. Navy students are assigned any and everywhere, and many are not assigned to the closest airport.
With respect to IFS as a screening program, I know one DOR and two that are having significant airsickness issues that may lead to redesignation since they are no longer prescribing meds to IFS students. So attrition does happen.
I think the quality of instruction is probably similar at most schools, but there are big differences in scheduling. Some places will get students through flight phase in two weeks if the weather cooperates, whereas at others you'd be lucky to fly once every 2-3 days and it takes you a month to solo.