I had the kalbi sandwich. It was ok, but I really enjoyed the kimchi fries.
They recently posted the health facts for some of the food here. Lets just say I ate about 1200 calories consuming the sandwich and fries! Was it worth it? I'd get the fries again.
The novelty behind the sandwiches doesn't really do it for me... Mind you, I'm a big fan of regular banhmi's that can be had for $2 in Chinatown.