Garageguy - Per PPG specs, it never requires sanding before recoat.
I'm not intending to make outlandish claims, this is what the PPG dealer said. The spec sheet posted in this thread gives the specs. PPG says "PSX® 700 is the world’s first weatherable epoxy that embodies the properties of both a high performance epoxy and an acrylic polyurethane in one coat." Then goes on to say "Gloss and appearance retention exceeding the best polyurethane".
NASA - "This data generated at Kennedy Space Center was used for the final version of the product. PSX-738 is a product designed to withstand twice as much continuous heat as conventional heat-resistant coatings (more than 2,000 degrees F),
Ameron's PSX 700 features a proprietary epoxy/siloxane hybrid formula that offers better protection against corrosion, abrasion and weathering than the highest-quality systems that combine epoxy and aliphatic polyurethane coatings. Accelerated weathering tests and field tests have shown that PSX 700's adhesion and resistance to corrosion and abrasion are superior to those of the best traditional epoxy coatings, while its long-term weatherability, gloss and color retention surpass those of top-quality aliphatic polyurethanes. "
PPG/Ameron Press Release - "Many of our customers find that a single coat of PSX 700 performs better than the traditional two-coat epoxy-polyurethane system that has been the industry standard for many years," said Dr. Raymond Foscante, Ameron's senior vice president, technology, and a key figure in the development of PSX product line. "In addition, the product offers significant cost savings. Since a single coat of PSX 700 can often do the job of multiple coats of conventional products, you save not only on material, but also application time. PSX 700 also has a far longer service life than competitive materials, so you don't need to repaint as often."
"PSX 700 adheres strongly to bare steel, coated steel and surfaces coated with inorganic zinc silicate primers; its 2,700-psi adhesive strength is more than double that offered by conventional epoxy coatings. When the product is used for maintenance painting, it requires minimum surface preparation. "
"The product is typically used on bridges and other steel structures, topsides and superstructures of ships, offshore platforms, industrial plant exteriors and interiors, rail car exteriors, tanks and piping, concrete walls and floors and many other applications requiring high-performance protection and long-term gloss and color retention. PSX 700 can be applied with airless or conventional spray equipment, brush or roller. "
"PSX 700 is part of Ameron's growing line of "environmentally designed" industrial coatings that provide superior protection while reducing the danger of pollution. Because the PSX-700 formula is extremely low in solvents and volatile organic compounds (VOCs), the product easily satisfies the most stringent environmental health and safety requirements and cuts hazardous waste disposal costs. "
I know nothing about the other products, but after readinfg the spec sheet, you'll be able to decide. I picked it because the Navy uses it on their ships and NASA uses it on their launch pads (good enough for my woodshop). I also like that when I wanted to touch it up or recoat I didn't have to sand. The wholesaler I purchased it from uses it on their floor and it has held up very well to traffic.