AF will give you more ground than ATP will. With ATP they expect you to show up with a lot of stuff pre-prepared.
With AF, look into which location you go to. Ask them how long it takes their CFI candidates to actually finish and get their certs at that location. Some FSDOs at some locations have reputations for being extremely difficult to schedule checkrides with. The 30 day program could easily turn into a 60 or 90 day program because of dealing with the local FSDO. Then if you have a scheduling delay expect to pay more $$$ to rent the plane to get proficient before you take your checkride since you may not have been in the plane for weeks between your signoff and the scheduled ride.
With ATP, they will submit your paperwork to a FSDO and airline you off to a location where they will be able to schedule a ride quickly. You will get done in 14 to 30 days, but they will push you through and you better come to class prepared or it will be a few weeks of hell. IMO, with ATP you get out of it what you put in. If you are not prepared, self-motivated and dedicated it will be a struggle, if you are prepared then it is a decent option for getting your ratings done quickly if time is an issue.