Do you plan to erect it yourself?
If not, locate local steel building erectors and find out if they will even do it, and if not, which brands of regular steel buildings they prefer.
There are dozens, no hundreds of regular steel building manufacturers out there, some good, some bad, and many average ones. You should look at them also if you are thinking of a steel building. Its a huge market and you need to do lots of comparison. MT and others sell because they do lots of nationwide advertising, not because they are an exceptionally good building (not saying they are bad, just that they are not the hugely great building everyone seems to think they are). As I said, there are lots of good metal buildings out there.
You don't say where you are located. Location, due to shipping costs is a big thing. That is partly why I said to look around locally. If you are in the southeast, I can suggest one or two metal building manufacturers that I know are good. One is a Rolls-Royce of metal buildings, and priced accordingly, the other is a Ford of metal buildings and you won't go wrong with it either. I've seem some that a Yugo could put to shame.
Charles