SoHo is freaking great.
I will agree that it is a bit of a shame you can't mix/match dumplings (if you get three dumplings, you get three of the same kind; if you get six, you can have two different kinds of dumplings @ 3 apiece).
Dumplings are absolutely delicious - I particularly enjoy their So Original soy sauce. It's great! On top of that, the service was friendly, even for a small food stand on a rainy day.
Price is also a huge deciding factor - some places are expensive around the square, but a small lunch for a single person for under $5? Pretty decent if you ask me!
Have gone back several times since I first put up this review - 100% worth it.