I hate Medco.
My company uses them for a prescription plan. They are the biggest pain in the rear I have ever seen.
We can get our medication discounted pretty well if we use their mail order service. However, if the prescription isn't written just so so, then it costs you more. They are the least helpful people I've ever seen. I had ordered and paid for some prescriptions on their web page, and used my debit card. I had let them store it so I'd not have to type it in in the future. MISTAKE!
More than once while refilling, I had marked for them to send me a bill to pay, and they automatically billed my card. That was a disaster waiting to happen. The last time this happened, I called them up and told them to take off the card since they can't seem to not bill me on it if they have it.
I guess they are better than nothing, but maybe not by much.