Black blob in the case of the EM "black hole". Invisible in the case of the standard cloak.

That's pretty incredible. So for the standard cloak does transmit the light from behind the object to the observer somehow?

I believe, from what I read in the past, that it actually bends the light around the object, somewhat like the way water will flow past rocks in a river.

These cloaks typically work by converting an incoming photon into a surface plasmon, a wave of electron oscillations. By carefully tweaking the surface geometry it is possible to get the wave to interfere with itself so that the photon is re-emitted at the opposite side of the cloak, at least if the cloak shape is symmetric enough.

http://en.wikipedia.org/wiki/Surface_plasmon