We install steel wall and ceiling panels frequently. It's very reflective, durable, easily cleaned, easily replaced or pulled back to do work behind it. Lots of pluses.
Cost comparison to sheet rock - assuming you pay for the installation - is pretty close to a wash since there's no mudding and painting needed.
Noise.. with insulation behind it, and once the room is filled with all the normal things that go into a room, it's really not a "noisy" room. This is customers' opinions, and I agree with them.
For hanging items, we'll generally ask the customer what they plan to hang, and we'll be sure there's blocking around the perimiter of the building at those heights. Using a spacer (to get past the ribs of the steel siding) makes it easy. When there's not a block where you need it, there's usually a post near enough to tie into (or you can remove a panel, add the blocking, return the panel to it's original spot).