Can Debt Management Companies Be Trusted?

I've been in a program for 10 months now. I've recently come into some money that will pay all these bill off. Now I'm a little conserned about sending a rather large check to the debt management company. They've been good in the past, paid what they said, but it just bothers me to send this much money to them. I wonder if I should pay the bills myself or let them do it. This is a once in a life time chance for me I can't screw it up.