My neighbor has had coverall building for 3 years now, it's a 170'x75' indoor riding arena. Here's pros and cons that I've seen. It's very nice to work in because it's white, easy to see inside, even on moonlit night. He has two vents in roof, between that and doors it stays pretty cool in summer. Snow and ice is a big problem, it comes off in large sheets. He puts up temp electric wire in winter to keep horses far enough away so they don't get hurt. It would kill a man if it hit him. Rain water also a problem, it was running back under the wood sides when it rained hard. He tacked up heavy rubber on the sides that extends away from building to push the water away when it rains hard. If you had a lot of drainage slope and tight bottom it would probably be OK. Gutters are an option, you might think about it. We've had extreme winds including a tornado less than a mile away and the thing stood up to that just fine. One huge benefit of the building is it's not considered a taxable structure, so he pays no property taxes on it. If it were any other kind of building it would be thousands a year around here, not sure what your tax system is like. The fabric is replaceable and it's not all that expensive. I think he told me replacement fabric was $10K, not counting labor, and that's a huge building. So even if it fails after 10 or 20 years, it's no worse than having to put a roof on a building. The floor in his is a mixture of sand and ground up rubber. The rubber still smells even after all this time and I find it kind of unpleasant. I don't imagine you would use anything like that in a workshop, but just in case, forget it.
He had all the work done by contractor, and I watched them put it up. I'd say for his size building it would be tough to do much of the work yourself unless you're a contractor and have experience with a crane and lift. But for the size you're talking about I think it's very doable. The steel elements won't be that big so you could raise them onto the tops of the posts if you have some kind of picker on your tractor, or a highlift. It's also not that hard to pull the fabric over the frame, but getting it tight in all the right places takes some monkey business. Just don't do it on a windy day. These guys ran around tensioning and loosening the thing to get it tight and get the ends on flat.
I talked to a company that puts these things up at a trade show and asked about coverall and their bankruptcy problems. He said the structural problem was under the condition of asymmetric snow loading: when part of the building had snow on it but other parts didn't, it could lead to structural failure. If the roof was uniformly loaded there was no problem. Anyway they faced going back and retro engineering all the units that were in snow country and that broke the piggy bank, so they had to declare bankruptcy. Take that for whatever it's worth. You're correct, I don't think other companies had that problem. If they did, they sure don't now. I would not hesitate to buy one if I needed such a thing, I've been really impressed with how well it held up.