I built all metal 30x42 with 12ft walls for a couple of 4 post lifts to do the dirty work in. Then I added on a 24x30 with 8ft walls for a clean room for engine building type of work. That room ended up with big screen t.v.'s and a pad for friends to come watch football and drink beer, lol. One subject nobody has brought up yet is with all metal your phone and wireless internet is compromised or might not get connection at all as in my case...this might not matter to some just throwing it out there to consider on wood to metal decision.
Not a problem at all... Just run Cat 6 into the building & a wireless router inside the building....