Looking at all the metrics you've mentioned, it's not the best in any one aspect. However, taking a step back, it's easily the most balanced 5K monitor you can buy. It does everything pretty good. For example, as you've mentioned, the alienware monitor is 2x more color accurate, but it isn't nearly as bright. No other monitor I know uses glass as part of the display rather than plastic. No other monitor on the market offers nano-textured etching to create the matte coating which provides the maximum optical clarity while providing industry leading anti-glare. No monitor offers a 6 speaker array capable of Dolby Atoms sound. No monitor on the market provides the deep macOS integration and is ready to go when you wake your mac in 1 second. No 5K monitor is cheaper than Studio display while providing the exact same construction material, design, functionality.
Anyone buying this monitor should not consider one metric, but looking at all the benefits combined. This monitor is more accurate than most monitors out there, offers 5k resolution, 6 speaker array, a camera that while isn't great provides center stage functionality, 3 mic arrays with noise cancellation for super clear voice and calls, nano-texture option, industry leading optical clarity for sharper and brighter looking display, and deep integration with macOS all baked into a single package. The better comparison would be LG ultrafine. However, that display has the cheapest plastic enclosure with an unaesthetically pleasing design. Another competing product would be Samsung ViewFinity S9. It gets close, but it uses the standard plastic matte material for the display, doesn't include dolby atmos capable speakers, doesn't have an included webcam that provides substantially better image quality than the studio display, and cuts cost by using a plastic back.
The bottom line is, for the price that you pay for, there is no competitor out there that can match Apple Studio display for the overall performance, functionality, and design (including use of materials).