AMK Products-what are the differences?

Just got my first AMK Heatsheet...haven't opened it yet to check it out (wanted to do a little scoping out before I fill all my kits with them.) and I got an AMK Emergency Sleeping Bag...looks about the same size as the Heatsheet, but all mylar, no orange poly-whatever. Then I got to thinking about the AMK Emergency Bivy, which is the same price as 6 or 7 Heatsheets.

Has anyone here used the Emergency Sleeping Bag, or Bivy, and would they be good things to have in my kits? From forum reviews here, I'm sure I'll be adding more Heatsheets to my kits, but are the sleeping bag and bivy necessary as well?

I have slept in the AMK Bivy once. Wasn't planning on it, but, one of the boys had a sleeping bag float down a river after swamping the canoe. (Lash everything to the canoe, how many times did we tell them that??) <img src="/images/graemlins/crazy.gif" alt="" />

I had a sleeping bag, and also had the bivy in my daypack. The youngster got the sleeping bag. I put on an extra layer of fleece, and used the AMK bag for the night. It actually was too warm. (This was a fall night, but, not really very cold, and no wind.) The bag had a nice feature I never expected I'd use until I was a little warm, there is a vent at the bottom, so you can get a little airflow around your feet, and keep the moisture going somewhere. The vent has a velcro closure. I did have a closed cell foam pad with me, so it was a pretty cushy set up. Normally I'd expect to have to improvise some kind of leaf bed under me.

I have always carried some kind of emergency bag or bivy in my daypack for hikes. I try to remind the boys that when you go out in the woods on a day hike, there are circumstances that someday may turn it into an overnight, so be ready for it. I no longer bother with the space blanket bag, because they are so fragile. They would be better than nothing, for sure, but, for only a little more bulk, I have something that's pretty usable, (and re-usable). I haven't used the heat sheet, so I can't really compare it.

I have used the emergency bivy bag, it's aluminized tyvek i think, quite good and more durable than emergency blankets especially the mylar ones. I have, but have not tried using the heat sheet from AMK. I just replaced my old mylar ones. If durability and weight are not an issue, i would go for the biv bag, if you can't spare the space or weight the heat sheet would be a better choice. Ideally both, you could then use the heatsheet as a tarp and would be very visible from the air.

The Heatsheet is polyethelene with aluminum coating.
The Emergency Sleeping bag is polyester film (mylar) w/ aluminum coating.
The Thermolite bivy is polyolephin (spelling?) and is much more durable / reusable.

If you can stand the bulk, the bivy bag is pretty good. Like the name says, it's a bag, so it's much easier to cinch up and keep your heat in, unlike trying to wrap a flat sheet around you. A lot of the minimalist hikers/campers use the bivy instead of those "look at Mr. Luxury Moneybags with his cushy sleeping bag." Sorry, it's a bit late.