bandito
Super Freak
It's more due to the formulation of the paint... While some of my Mk.4 and 6 have faded (I've 4 each, all with the relative same exposure)... none of the Mk. 5 have faded (& I've many units)You're comparing different rubbers. Car tires are composed of many different layers of things and they're designed to be sustain form against weather conditions.
I'm pretty sure a lot of people play around with these a bit and then settle them. The rubbers used in those are possibly cracking due to paint and whatever conditions they're stored in. There's a lot of varying factors to consider before you go and spew off Hot Toys makes etc etc crappy rubbers. I'm sure a lot of people still have their Leonidias in perfect condition. All those pictures posted above are like mad isolated and very few cases.
The oily abs... I don't know what the deal with that was, but they sure as hell didn't let the dyes dry off properly or the material just wasn't properly mixed well together.
And the thing about the Iron Man fading... red colors fade the fastest due to exposure to violet rays. I don't know the case for that guy or whatever, but any sort of red colored material will fade. If you've ever seen posters on windows of stores and stuff, over time they turn blue/green because the red fades. It's the same here, not really the rubber's fault.