Which manufacturer’s have gone to this ?
Quite a few.
Do you have one ?
Yes and no. Currently out Fiat 500 is the only car in the garage that has this system.
Previous cars were the Porsche Boxster, and the Chrysler Crossfire.
Have you changed one ?
Much more than one.
Are they messy ?
Depends on your definition of messy.
The Porsche is potentially messier, but I keep a drain pan under it as I unscrew it.
The Crossfire was cleaner, as its mounted on the top of the engine, and if you unscrew it slowly, all the oil drains down into the pan. You still have to oil up the new o-rings, and pop them back into their proper slots.
Honestly, no, they are not more difficult.
Though I have heard that the ones on certain Toyota engines are a bit more of a hassle to do.
No direct experience, though.
Trying to manhandle an oily o-ring without damaging it is always a problem.
What about the element ?
Elements are usually pretty sturdy.
Some are paper, others are a fleece type material, like on BMW and Mercedes products with long oil change intervals.
Sometimes an aftermarket kit can come with o-rings for different applications, and you might not be able to tell which ones are the ones you need until you have tried in vain to get the wrong o-ring on for the past 5 minutes.
Don’t really understand this question.
Is the “can” stainless steel ?
Dealer only at this point ?
Not unless something breaks, or you have no clue what you are doing.
Expense relative to conventional throw-away ?
Some are more expensive, and some are less expensive.
Depends on the application.
Are they all going to this style ?
No idea, but in the long term, probably yes.
Less waste at the landfill is always s good thing.