They CAN be difficult because there are so few spots available. Unfortunately, most are in the midwest (Michigan and Ohio) and it of course helps to have ties to the area. I interviewed at four, but decided to go through ERAS so I withdrew from the DO match. I learned one thing while I was interviewing....if you didn't actual do a rotation with them, they won't be very interested at all.
All the programs are basically "community programs" where most teaching and conferences are resident run. So if you want a really academic environment, you likely won't find what you are looking for at a DO program. The closest to academic programs are going to be in Michigan because all the residents from all the programs go to MSU in Lansing, MI for an all-day conference. Because its such a large audience, with DO residents and MD ones too, they get pretty good guest lecturers. The drive just might wear you down after doing it every Tuesday for four years.
I interviewed at Pontiac and at Henry Ford Bi-County/Wyandotte and was fairly impressed. I would recommend you check them out, and of course rotate through there if you can.
From what I understand, DO's will be applying for DO residencies through ERAS starting next year, so although your applications will be easier to send out, the DO match will still come early, and I guess you can withdraw from the DO match if think you have pretty good chances in the allopathic match. And on the flip-side, if you aren't getting many MD interviews, it might be a good idea to go ahead and rank DO programs...that way you'll at least be a radiologist. It can be quite a gamble.....good luck.