I have to disagree with the evaluation of the DriDucks poncho as far as durability. I think the fabric is actually more appropriate in a poncho than a rain jacket as it doesn't have the seams at the arms and sides that are stressed under a pack. I think any of the ultralight silnylon ponchos would have difficulty surviving a sharp branch at walking speed. If the DriDucks poncho has a fault, I think it is that it isn't a true backpacking design-- it should have an extension on the rear to give full coverage when wearing a pack.
I think evaluating the Hennessy Cape as a ground shelter isn't a fair use of the product. It is designed as a minimal cover for an asymmetrical hammock and can make use of the tapered ends, where it leaves the user too exposed for ground use. The standard cape is made to the same dimensions as the standard Hennessy Asym rain fly and comes in at the same weight as the stock polyester fly, which I thought was a pretty good trick. I use the XL Cape with my Expedition hammock, giving quite a bit more coverage for a couple ounces more. The XL version is 69" x 110" (137" ridge line) vs 63" x 99" (132" ridge line) for the standard size. MY XL cape doesn't have the line pockets, but I wouldn't trust them for use on the trail and would expect the lines to fall out and create a tripping hazard. I think the Hennessy Cape is good for an occasional shower rather than spending all day in the rain with it. I bought it with summer trips as a CYA option where rain isn't expected. I use a 9.5'x12' tarp for shoulder season coverage with a hammock.
If you want to use a poncho with a hammock, I think a poncho makes a better under cover than a rain fly. I had a silnylon poncho made that has shock cord in channels on all four sides, and a slit head opening with a 3" tall collar--- it is a hoodless design. It goes on the bottom of my Hennessy Expedition in the same way that the Hennessy SuperShelter is used. I can use the under cover/poncho with the open cell foam insulator from the SuperShelter (it is available separately) or a conventional under quilt, or Garlington Insulators.
My poncho under cover looks much like the hoodless poncho design by BPL in use:
My poncho as an undercover on a Hennessy Expedition hammock