rex -
Although not common, I do use minwax polys at times. A couple of weeks ago I actually laid a tile floor in a kitchen I had repainted some months ago, and I had to install an oak threshhold at the doorway between the kitchen and living room. LR has oak hardwood floors, so I chose an oak threshhold to match. After installation, it needed poly to match the floor. In my tests of different products, the minwax oil-based poly in semigloss was the best match, and I used it with great results.
In this case, I could tell that the floor had been finished in the oil-based poly because of the amber coloration to the poly... remember that the water-based poly has absolutely no amber coloration whatsoever, so the 2 different products do NOT match in the coloration of the finish. Also, the water-based poly has a very limited lifetime in my experience, but the oil-based poly tends to be exceptionally strong by comparison. Due to this, I really don't use the water-based poly at all.
But I agree that the minwax oil-based poly has really changed a lot in the reformulations that have occurred - the overpowering smell has all but disappeared, but the workability has suffered. You are correct that it has to be laid down thinner now than ever before, and sanding between coats is now absolutely essential to achieve a fine finish and to avoid delaminating problems. Also, I find I get better results if I really take my time to slowly stir it up from the bottom, as the newer formulation seems to "separate" a lot more than it did before - and an inadequate mix will yield even worse workability.
But minwax's polys are not my preference. If I have the choice, I too prefer Varethane or ZAR polys. I'll have to check out the ceramithane, it sounds like a nice product. And there are some really amazing marine-grade coatings out there too, as they are formulated to endure some of the most extreme environmental conditions on the planet.