Lastolite Ezybox on location
We did a shoot on a beach using the Ezybox. Nikon SB800 was mounted on the Ezybox and then it was mounted on a regular lightstand. Some mild wind was blowing but the Ezybox held up pretty well. It only fell over twice and we were able to catch it before damage was done.
When I set it up, I tried to make the legs of the lightstand as wide as possible. Then I pushed them into the sand. I put my camera bag and another equipment bag on top of them. In general, that worked very well.
The Ezybox gave pretty good light but I found that it maybe too small for full length shot and I have the bigger version (60cmx60cm). Also the light fell off quickly, so it cannot be placed too far from the subject. Since I had to move it close and I had to make sure I didn't have it in the frame, my wide-angle shots were limited.
In summary, I think the Ezybox is very easy to carry around, very easy to setup and used. It gives good light but it is not the perfect solution for full length shots.
A big shoot-through umbrella maybe better, but the chance of getting it blow over will be higher, I think.