I tried this place out (after a couple failed attempts due to overcrowding) a few weeks ago, and have to say the food was great. My dining partner and I had the pork belly steamed bao, siu mai and pork and shrimp dumplings. Everything was hot, tasty, and spot-on in terms of texture. Great selection of drinks and fun toppings/sauces available as well.
We wanted to try some different menu items so we stopped by yesterday at 2:30pm on a Saturday, to find it was absolutely packed with people. It was just too damn cold to wait outside, and to risk having to stand and eat if we couldn't snag one of the very few barstools wasn't worth it.
Being a hole-in-the-wall establishment might not bode well for Mean Bao during the winter. I hope in warmer weather they place some tables and chairs outside - or just move to a larger place. Again, the food isn't to be missed, but you really take your chances with seating availability.