Obviously, this topic is pretty controversial. There is has been a lot of pseudo-scientific information bandied about, and very little hard facts. As much as people say they have tested different products, no one has ever disclosed their test protocols, products involved etc.
For example, some people say petroleum distillates are the harmful elements. But this is misleading in that petroleum distillates is an umbrella term that can be used for everything from vaseline to acrylics to kerosene. I find it amusing that some of the people who make this statement also advocate using sealants, many of which do have petroleum distillates (e.g. some Zaino products are known to petroleum distillates - check out this thread, and the response from Sal Zaino himself http://forums.corvetteforum.com/car-...tes-in-z5.html
). My point is that not all of these chemicals are bad, and the pseudo-science bandied about may do a disservice to products that actually work quite well.
As for the butane argument, I take that with a grain of salt. Butane is pH neutral, so I don't see how it can denature polyurethane. Also, butane not an active ingredient in Plexus, it is an aerosol accelerant. As long as you hold the can at the appropriate distance, the butane should evaporate well before it reaches the PPF. If there is some other complex reaction involving butane that does cause a problem, I would very much like to understand it (and at that point apologize to anyone/everyone that I argued with)
Being someone who has had good results with Plexus, I'm reluctant to abandon it. But if someone can outline their actual test results, performed in a controlled fashion that definitively point to the product being bad, I would stop using it in a heartbeat.