Thanks to both of you for your opinions, both of which pretty much agree with my own instincts. But neither of you indicated that you have actually used this 450 product, and when I asked for a review of it, I assumed that whoever is going to do that should have actually tried it first. Years ago I used to use an excellent polyurethane made by Red Devil, but it's no longer available. I've tried a lot of others, but in my opinion all are inferior to the Red Devil one. That includes the popular MiniWax product which I was so disappointed with, I consider it to be unacceptable. I even tried conversion varnish, and although I found it also to be excellent,I'm just a homeowner and can't provide the safety precautions one should follow when using that product. It's also very pricey and hard to find. My experiment with the conversion varnish is shown on this website.
and it was used on both the mantel and the surrounding cabinets & shelves, all of which I built from scratch and finished in my garage during the summer with the doors wide open.
A fast drying, water based varnish would be nice to use if it can provide a quality finish. Has anyone not associated with the manufacture or sale of the 450 found that to be the case?