Ah yes, they are good. In fact, it was used here in my latest diorama if you want to see.
Right here.
My brother picked them up at I think a Micheals shop, he got the red ones. When we wanted to make something we stuck a piece of a toothpick in between the adjoining blocks and then glued them together with Elmer's glue. The wind isn't a big problem if you have something to hold them up or make the walls reinforced. They are REALLY light and tend to fall even while shooting; at least with us, since the walls we made for the sewers aren't really reinforced. I put books on the other side of the walls to hold them up. They look good however.
My brother and I made a few separate walls and a sewer tunnel. They can be shot one way, then can be reconfigured with another wall against another hallway. I'm about to spray paint them grey to give them a more urban feel.
I've had them put together for over a month and they're still holding. I would definitely recommend them.