My
Scamp has RayFoil (like Reflectix), topped with marine headliner (sort of like a thin, unbacked, slightly stretchy carpet). They have used it since the mid-80’s, and it is durable and more effective than the numbers would indicate (though Scamp’s claim of R-15 is absurd and based on a faulty reading of the specs). I like the soft touch of the headliner when you brush against it on a chilly night. It can be vacuumed, spot cleaned, or steam cleaned as needed, and it does not absorb moisture or odors.
While unfaced closed cell foam (Ensolite) topped with headliner would be better performance-wise, the Reflectix is much cheaper and easier to install. Since most heat loss is through the
windows and vents anyway, I honestly doubt you’ll notice much difference between the two in actual use. We’re only talking about a quarter inch of either in typical installations.
Your call.