The Hennessy is solid (breathable) material on the bottom, the IMPS isn't, the HH model I have is rated for 250 lbs (will hold more), the IMPS is good for not more than about 200 lbs, the hammock/net/tarp are all-in-one and lighter than the IMPS, netting, and tarp sepparately, and you (I have) can roll out of the IMPS without much trying. I have an IMPS that I carry for it's MANY other uses, but I VERY MUCH prefer to sleep in the Hennessy. Just two cents from somebody who has tried and STILL uses both. And yes... I know, for those of you who like to travel light, I carry WAY too much gear <img src="/images/graemlins/grin.gif" alt="" />
Troy