I have the Hennessey Explorer deluxe and I just purchased the Fourseasons undercover. I added the reflective blanket and I cannot believe how much heat that it puts off, it's almost like a space heater underneath me. It's only 65 for the high today in Seattle, so I thought I'd try it out and it's almost too warm with that reflective blanket underneath.
I thought the mat was going to be a pain and interfere with the getting into the hammock. Since you sleep at a diagonal anyway it's very easy to get in you just can't move around and expect your feet to be fully covered unless you reach down and move the mat which I don't do and haven't done today. It just because it makes it so much easier to get in and out. I like the overall system. A winner.