To call someone naive when you reply with something incorrect is... well, pot calling the kettle black and all that.
There is very much a difference between DO and MD. Almost all DO schools don't have institution owned/affiliated teaching hospitals. This is one of the reasons DO schools can be much more expensive, because they have to pay external hospitals larger sums of money for rotations. As such, DO doesn't lend itself to academic and research medicine the way MD does, due to the lack of teaching hospitals and labs, and subsequent dearth in funding.
Another difference is that the DO degree isn't recognized globally the way MD is, specifically in a handful of South American countries, most of Africa, eastern Europe and parts of Asia:
http://www.osteopathic.org/inside-a.../Pages/international-practice-rights-map.aspx
There is definitely a struggle for DOs to place into some top residencies. The merger is a questionable fix to this, but it calls some concerns that it may actually make it harder for DOs to place in top DO specialities that will now be available for MDs. Regardless, the system won't die right away and it will be hard for a long time for a DO to place in some top speciality.
Last, and this isn't truly important, but some people care about going to institutions that have tradition and have been around for hundreds of years. Just something to consider.
Anyway, I'm not knocking DO. I think it is a fine choice. I applied DO too and if it was the only degree program I got into I would be very happy to attend. But saying there is no difference is... well, naive.
So, to quote yourself: