Hey anoko! I haven't run any traffic to Puremeds offers, but a lot of big volume guys are using them. I have been working with OAInternet for a couple of months running their straight sale offers. They pay on time without any hassle. As I said before they do have a free trial offer, but it's in BETA.
They are the only two companies that I am aware of that have free trial offer in this niche other than Market Health. If you are looking for straight sale offers, there are a good few other companies that haven't been mentioned.