although i'm a strong supporter of JetHot, I think Swain's coating offers a significant advantage over jethot.
-It is thicker than Jethot which means it will insulate better.
Since the APS header is made of 310 Austenitic Stainless, it can handle the higher temperature that you'll force it to see with the external-only coating that Swaintech applies. I'd say Jethot is definitely preferred for parts that are either made of lower grade steels or have slight fitment problems. With higher grade steels that maintain much more strength and corrosion resistance at elevated service temperatures (like 310 or 321), the Swaintech becomes a more viable option, in my view.
Still though, I've seen the extreme durability and toughness of the Jethot and I trust it very highly. I am not 100% sure which I'll choose for my own APS header when I get it.