I know very well what it is known for. I'm questioning this whole perception. What is it based on? Who is behind it? Who is watching the watchers?
So far, in this whole thread, the best answers I get are A) rabbi Genack or B) perception is enough.
It seems that everyone here is basically of one mind in responding to you.
If you truly wanted to be machmir and discriminate heavily on what hechsherim you use, no one would have an issue. Your issue seems to be more boycotting Modern Orthodoxy (if you knew how much they relied on Chabad mashgichim, you'd boycott even faster).
But even if your issue is questioning the reliability, what keeps on being repeated is that the OU is extremely reliable in that they are experts in modern day food production and halacha, and they are extremely consistent and systematic.
Even the many who do not rely on the kulos and heterim OU does, rely on their process and transparency to know what they can and cannot eat.
Their advisory board is public. Their rabbanim are public. As are their psakim and methodology - arguably more so than any other hechsher.
The very "Heimishe" hechsherim you are so willing to trust, themselves trust the OU implicitly.
Those are the facts on the ground.
Your real issues of money and/or politics sadly affects virtually every single hechsher. You have HUGE blind spots when it comes to modern orthodox (and Chabad), which is what drives you to boycott.
Generally, what people who are looking to be machmir do is find someone they trust who is involved in the field, and they will tell you what type of products of the OU (and the OK, and every other K) you can rely on without worry and which products may be problematic.
My father has worked in hashgacha for more than three decades. Some of what he himself certifies as kosher, he does not eat. (on the issue of chalav stam, for instance, he lands to the right of @Freddie but it is approved by the hechsher.) Even though my father is not technically on the Beis Din that gives the hechsher, you can bet that when Rabbi Rubin, Levy or Genack have a question about a product, they'll quicker be calling his number than the dayan who's name is on the hechsher. He was the one in the factory, not the dayan.
If you or any other non kashrus expert calls him, he'll gladly let you know exactly what shitah, kulah or psak they relied on to certify any specific product. Same thing with the OU, OK and others. Though they may approve certain items, they'll let you know that it wouldn't meet your standards if you picked up the phone and called.
There are many bnei Torah who actually know what producing cranberries entails, and are only too happy to share their knowledge. You'd do well to ask them, rather than "blindly follow" someone who's name happens to be on a package and isn't modern orthodox. But again, that's only if your motive is being more discriminating in your keeping of kashrus and not the Mitzvah of החרמת מאדערן ארטאדאקס.