Phil - The my metal studs measure 0.016" - which is roughly 27 gauge, if I did the math correctly.
I'm not happy with mine.
They are quite easy to work with, and theoretically last longer than standard wood studs.... but I'm not sold.
The major problems come with hanging things from them. Because of the tiny contact area (0.016" metal, versus 1.5-3.5" wood), screws do not like to stay where you put them. I have had several pictures fall off the wall, just from vibrations slowly eating away at the sheetrock, while the metal stud acted as a pivot point for the screw. (I don't use nails for anything. They just destroy walls.)
Usually, the stud gets bent in the process, and the hole stripped. So, I have to punch a new hole in the wall, or use a bigger screw (which doesn't work, since the sheetrock is messed up).
I prefer the solid mount that is achieved by having a substantial amount of wood for attachment.
I have three basement walls that use metal studs. I have one removed for electrical access. It will be replaced with wood studs, when the wall goes back up - since it is the shared back of a two opposing closets, and must support shelves on each side. Another wall needs to support the TV in our home theater. I don't trust the metal studs, and have already rebuilt that wall with full dimension 2x4s (I needed the extra 1/2" for an in-wall power center, and hidden wiring pass-thrus.) The third wall is non-critical, but if I ever open it up... it's getting wood studs.
The only thing I can't comment on, is moisture. I live on a slope, over good drainage.