Just getting caught up on some of the older threads...

My sock is much easier to rig than any tarp b/c I leave it on the hammock. I hang the hammock and the sock is no additional rigging.

I've only had condensation in the sock a couple times, and only once was it excessive enough to even warrant not packing it up with my underquilts (and that was b/c my son and I were both breathing into it on a foggy night). OTOH, I've had lots of nights with condensation on the bottom side of my tarp...which is a pain if the tarp is pitched low on a top loader b/c I always brush my back getting in and out.

I've never seen a tarp that adds 10F (measured) of warmth to a hammock...at least not for the weight difference of a hammock sock. Possibly the Hammock Hut or a fully closed up winter tarp would come close, but I haven't seen anyone post measurements of that yet.

And with a hammock sock you never have to worry about wind shifting directions b/c you're fully enclosed.

I really like sleeping w/o a tarp so I can see the sky. With a sock, I can still get some wind protection while poking my head out, and I don't have to worry about dew or condensation wetting my quilts.

I like bigger tarps for some conditions as well (testing one now, actually), but I think the hammock sock concept has some strengths that shouldn't be overlooked.