As a DO I will admit that the osteopathic residencies are not up to par with most MD programs, in terms of volume of surgery, number of faculty, opportunity for research, fellowship opportunities and convenience of peripheral rotations. Just look at their website (if they have one) and that tells you alot about the program.
The best way to learn about the program is to call the program and ask to speak with their residents, the more the better but definitely, both a chief resident and a lower level resident. (Forget the PD).
Ask questions and try to gauge their response. No program is perfect. If they have only good things to say and try to sell the program, you should worry. If they are honest, it shows in their response and tone of voice.
Regardless, you can become a well trained, capable surgeon if you go to most of these residencies. Also, ultimately you really learn about a program only if you attend the program by rotating or through residency.
