I'm doing polyurethane on a plywood floor right now, that will get a lot of traffic. Just a small portion of the floor for now. About 150 sq. ft. And then more later. Will let you know how long it holds up.
I've been beating the hell out of a Varathane'd table I refinished. I grind on it, slam very heavy fixtures on it. Hit it with a hammer by mistake a couple times really hard, and so far, so good. I'm amazed how well it's held up. I used Varathane clear high gloss floor finish. Water base, unfortunately, because I was told that they're getting rid of the oil based stuff in California. At least at the HD. Anything that works or does the job, they get rid of.