For anybody interested, see this article:
http://store.carcareonline.com/vinylcare.aspx
There is some description as to why you don't use Armor-All. While the article doesn't call out Armor-All specifically (probably due to possible lawsuits). over the counter silicone oil based products only points to a few products, Armor-All being one of them, and is easily the most widely available.
A video about this:
https://www.youtube.com/watch?v=eEkupIubAnw
Whiie he is placing the blame properly on Armor-All, his reasoning is faulty.
From my own experience, on a 1988 Chevrolet Beretta, and from what I have read in many other places, the problem is with the way Armor-All is designed to work. Armor-All's basic ingredient is silicone oil, which gives that new car vinyl look by attracting the "plasticizers" (plasticizers are chemical compounds that help keep vinyl flexible, and part of what makes vinyl different from hard plastics) that are part of the chemical structure of vinyl, to the surface of the vinyl, as they would be in a new car. Problem is, those plasticizers are broken down by UV, which is why they out-gas out in the first place. Long term, over a period of say, 10-12 years, enough of the plasticizers have come out of the vinyl's internal structure that the vinyl is no longer flexible. Now, when the car gets exposed to intense sunlight, and would normally cause the vinyl to expand, the vinyl, having its plasticizers depleted, can't. But due to the heat, it must. This gets resolved by the vinyl cracking. There is some debate as to whether the silicone oil causes the plasticizers to migrate to the surface and break down, or if the Armor-all itself is absorbed into the vinyl and is destroying the plasticizers below the vinyl surface. I personally think that the Armor-All is attracting the plasticizers to the surface, where the UV is breaking the plasticizers down. The same electrostatic attraction that brings up the plasticizers is also what make Armour-All the most amazing dust magnet, attracting any dust particles within a few feet.
Have you ever noticed a brownish residue in the crevices,nooks,and crannies in a vehicle that has been Armor-Alled over a period of years? That is UV destroyed plasticizer residue mixed with the Armor-All silicone oil. Look for it on any Armor-All treated car.
Some of this may not apply to all vinyls, as vinyls will change over time, and even from vendor to vendor if multiple vendors are supplying vinyl parts for same car within a model year. By my description above, you can also easily see that this is also related to sun exposure, temperature range, and how often Armor-All is applied.
If you think any of this is made up by me, do a web search on "armor-all damage" and look at a few of the links. This isn't just a single time, or single person, occurence. There are a lot of good vinyl care products out there, aside from the ones that I have mentioned. I just know that Armor-All isn't one of them.
Kostas