The metal building will not be a problem, but the cheapie router might. After trying low and mid range blue routers we went with a business class system from Cisco. Huge difference. Don't cheap out.

A bit. We use the Aironet from Cisco. High capacity, great range, mounts on the ceiling for best coverage. Our building is two stories, each floor about 9000 sq ft, so we have four of them and get outstanding coverage, corner to corner. Previously we had four blue routers, plus a number of repeaters. With those we had spotty coverage and very poor hand-off if you moved from one area to another. The Aironet does cost about 50% more than that mess, but the coverage, seamless hand off, and much greater capacity (more users) made it a bargain, especially when you factor in the time it was taking our IT guy to fiddle with the problems we had with the pretty blue boxes =]