I'm pretty sure you
literally said "popping up shareware nag-screens at random intervals" instead of "that's equivalen to", but whatever, I'll take your word for it, in good faith, that you did not edit your post and that I read your post wrong.
Like I said before: errors during redeploy are not supposed to happen even in the open source version, and if they do happen then we are very interested in fixing them. Please tell us more. There is no need to spin this as being "dishonest". If you don't believe us, tell us about your problem, let us fix it, and verify for yourself that it is fixed. Only the facts matter.
As for the Engine Yard and Uservoice.com post:
1. All problems that the Engine Yard post talked about, were fixed 2 days after they published that article (http://blog.phusion.nl/2012/09/21/the-right-way-to-deal-with...). If you are still experiencing those problems, tell us, and we'll fix it. By the way, did you notice that EngineYard said something entirely different about Phusion Passenger and Unicorn later on? https://www.engineyard.com/articles/rails-server
2. Almost all problems that that the Uservoice.com talked about, have been fixed in Phusion Passenger 4.0, open source version.
3. There are also plenty of posts that describe migrating from Unicorn to Phusion Passenger, e.g. https://speakerdeck.com/arnvald/dot-dot-dot-but-we-had-to-ki....
So what does that mean? Experiences differ, for all sorts of reasons, some legit and some not (e.g. inefficient configuration). Neither kinds of posts automatically mean that Unicorn/Phusion Passenger is bad: there will always be people having problems with a particular technology. That's why we encourage people who have problems to contact our support forum.