Regarding Visas as a DO. I'm right in the middle of that process now, and I'm rather pleased with the results. Of course, I didn't receive as many invites as my US AMG colleagues, BUT, I am definitely beating out all the IMGs who are foreign citizens. I would say I am receiving twice as many interview invites as a foreign IMG applying to the same spots (who have higher board scores than me), and I only applied to half to 1/3 of the number of spots IMGs applied to. So I'm doing pretty well. I ended up going to more interviews than US AMGs simply because they can afford to cancel on interview invites. But I accepted all my invitations, so even though I received less invitations, I will end up going to more interviews than the AMGs.
I'll write another giant thread over at premed101 after this process is over, and I match.
Specifically, I'm doing all FM. I could have applied to psych, or IM, but I decided on FM solely.
I got 15 interviews, at really famous programs as well. 14 agreed to H1B sponsorship (these are dually AOA - ACGME accredited programs, or only ACGME accredited, (I didn't do the AOA match) I'm applying to the ACGME side), and only one J1 site (which I'll rank low for obvious reasons).