I was with a DMP, LIghthouse Credit Foundation, for about 6 years. And ultimately, I paid off all my cards by getting a personal loan with a fixed APR and pay-off date. During my time in the DMP my scores fluctuated wildly as there were other issues going on, but I do know that my three credit cards were paid on-time every month. And that probably kept my score from tanking to the low 500s.
I chose the personal loan, because no matter what happened I was accruing more interest, and my UTL dropped substantially (as while you're in a DMP, you lose the CL, but still carry the debt, so you UTL could end up well over 100%, something to remember). Also, the personal counted as a different kind of credit on my FICO report, so that probably boosted my score or kept it afloat... depending on how you look at it.
There is life after DMP, but you can probably avoid it all together. If you're looking to have a single payment, then go for a personal loan, your scores seem high enough that you can get one with a good APR. Then you'll have only one payment, and you will drop yout UTL considerably WITHOUT slashing your CL.
Just remember to cut those credit cards, and leave a 1% balance on them. That's the score boosting method
