As of November '04, guys who DOR'ed out of aviation before API were unable to compete for an MOS. Translation: most got supply. If they were $h!t-hot dudes, the company staff tried to hook them up with cool units, such as a Recon Bn.
On the other hand, most cases of DORs and attritions during API and Primary (that I've heard of) ended up with some kind of Intel. DORs tend to be looked less kindly upon than attritions.
Everyone you talk to will try to convince you not to DOR, but the decision is yours alone.