Before we get all warm and fuzzy about private/industry sources for medical research funding, we need to be aware that if a study is funded with industry money, the sponsors of the study can and do squash studies that are not favorable to the sponsor. The recent issues with antidepressants and an increased risk of teen suicide is one of the most recently publicized examples of this, but this goes on all the time.
I'm a pediatric oncologist that works in academics, and our division is frequently approached by industry to do clinical research sponsored by private funds, so we see a lot of this. Industry always reserves the right to do what they want with the dat, including refusing to submit it for publication. I don't know of a single physician worth their weight in salt that doesn't automatically see industry sponsorship and think, "potentially compromised data".
This is not to deny that private funding sources aren't important. But if funding comes from the public sector, I have more faith in the data.