2) Rotation Sites AND Rotation subjects: Some schools make you do OMM rotations in 3rd year and some do not. Some schools have Emergency Medicine as a 3rd year rotation, and some do not. Look at the number of electives offered too in 3rd year. Ask yourself: Are you REALLY going to a D.O. school to focus on OMM and are you really going to use it in the fields you want to go into (assuming you think you know what you want to do before school starts). If you are interested in EM, you may want to lean towards a school that offers a 3rd year rotation. Look at Touro-NY as an example and their strong match history into EM. Next, what is the QUALITY of the schools rotation sites. Also, Hint: at every interview every school will claim they have solid rotations....and talking to older students while interviewing will yield a useless bias (obviously any med student taking the time to tour or interview pre-meds loves the school and may not represent the average student). For example, my school apparently has "good" rotation sites according to some on SDN yet we have numerous sites where students see 4-5 patients per week split between several students. Are you really going to learn a lot like that?
You will not receive a solid education at every DO school. Some schools offer an OK education, some bad, and some great. Dont be foolish to think they are all the same with tuition and location taken out of the equation. In the long run it might not make a difference (every school has amazing students), but when you go to study for those board exams (which can open or close a lot of doors) you will want a solid background......and when you go to get those reference letters during your Sub-Is in 4th year, you are going to want a solid 3rd year rotation experience
Edit: Of course if you want to go into the traditionally "less competitive" fields, this matters much less