I disagree with you on sound quality, I prefer the AirPods though both have their advantages. The Beats X do have better noise isolation, but that isn't the same as sound quality. And which is better for you depends on how isolated you want to be. For example, if walking/running outside around roads, it is likely better to have less isolation, so you can hear traffic. If you are in an office, you may or may not want isolation, depending on if you need to be able to hear co-workers when they talk to you.
Also, if you frequently use your phone when wearing your headphones, the AirPods are better, as they tend to work very well -- to the point that, for many people can't tell you are using them.
A lot will also depend on fit; while AirPods do work well for most people, and you can also use the foam cushions that are sold for the EarPods, the AirPods can't really be adjusted for size; where the Beats X can be sized to your ear, as well as wingtips to help make sure they stay in your ear.
The last thing, at least that I think should be added is, if you want inline controls, you will want the BeatsX. That is one place the AirPods don't measure up -- it can be somewhat mitigated if you use an Apple Watch, but they are much less convenient for changing volume or switching tracks.
If you have a local Apple Store that has both on demo, unless one or the other clearly fits you better, I'd go and try both out -- though I will say that the Apple Stores I tried didn't have the BeatsX to demo (I believe I asked at three Apple Stores). I bought the BeatsX and ended up returning them, since I couldn't demo them, and found -- for me -- I prefer the AirPods.