I have carried 2 - 4' x 8' sheets of 5/8" plywood; however, mostly I just carry 1 sheet at a time. So, whatever that weight is. I have probably moved 40 - 50 sheets of plywood with it. That's for multiple projects, over a year's time.
I understand your question. Nowadays it often happens that manufacturers make "brand" videos that talk about the company name while completely ignoring any salient facts about the item itself. I find this annoying. Whenever I see that type of brand video, I exercise the chance to vote it down or "un-helpful" whenever possible. The entire point of providing information is to help customers make good choices. "Branding" only makes unreasonable emotional attachment to brand names. And in today's world of mega-conglomerates, where almost all great tool brand-names were purchased, then had their reputations ruined by cheap overseas labor, branding is even more useless. So, although I don't know the exact video you saw, it is very likely you saw one that made no mention of this product, but only talked about the NAME. If you want your question to have some positive benefit, I suggest you write a quick email to company headquarters, addressed to the marketing department. If enough consumers tell companies we do not appreciate these branding videos, then they will start to pay attention.
I've not tried carrying anything downstairs with this, but it depends on your ability to get up and downstairs and the room that exists. If you can carry sheet goods with this you might be able to do so. I can only carry one piece of dry wall or plywood sheet at a time with this.
Yes
These are made in several facilities, mostly along the Asian rim: Most are now made in China, although I have seen some with the CoO mark from Taiwan, Vietnam and Israel.
Not by itself. Uhhh that is what it was designed for!! If your're exceptionally talented you can carry drywall too.
I wouldn't recommend it, it made carrying on sheet of 1/2 inch managable, but I think 2 would be more than you want to tackle.
no
Durable- and ridged thick plactic
Although these are mainly for carrying sheet goods, removing Jeep doors is another clever use of this item. My son has a Jeep and he uses this for his doors too! ;-)