I have an xbox one X and a ps4 pro (and a PC 1080ti + Rift) and think the X is just fine, I'm playing AC Origins and Forza 7 on it. The list of X enhanced games is small BUT it automatically does a shit load of stuff to 360 BC games to make them WAY better looking, to the point where the X version is BETTER than the PC version for stuff like Assassins Creed 1, the Mass Effects (without mods), etc. I want to play RDR but glad I waited for X, it looks WAY better on X than it did before on S.
Newer games seem better on the X for the most part, for example AC origins or Battlefront 2 runs at a slightly higher res and there are no FPS drops whereas PS4 Pro I guess has some FPS drops sometimes in MP but to be honest I've never noticed it. AC Origins only supported 4k HDR on X for a while, now I think its on PC and ps4.
End of the day I see it this way: if you are GONNA play on xbox, you should play on X. The stock versions of games on an xbox one S is almost always worse than the basic PS4 version, usually like 720p or 900p vs 1080p or framing/AA issues. If you can ONLY pick between an X or a PS4, go PS4 for exclusives. Pro is worse than X, but better than xbox one just because of exclusives. It doesn't matter how many fucking extra textures Gears of War 4 or Halo 5 have, I'd rather play Horizon Zero Dawn, Persona 5, Yakuza 0, Bloodborne, etc. I can rattle off 5-6 games I wanna play exclusive to PS4 in 2018 but really can't name one for X, i don't honestly give a shit about Pirates of the Sea or Crackdown and anyways I could play both on my PC anyways.
From a technical standpoint the X is FANTASTIC. Its very quiet, its solid and small (almost exact same size as One S which is amazing), and everything just runs faster and smoother on it than my previous one S. I'll probably buy future SP only games on the X, like Far Cry 5 and stuff. Not sure about multiplayer, I bought Battlefront 2 on PS4 but wish I was playing on X instead. The elite controller of X just blows away the regular dual shock 4 in feel and comfort. Its too bad the hardware and operating system group of Microsoft is sooooooo far ahead of the "we should really get some exclusive games for our console" group.
I'm expecting at E3 next year either Sony or Microsoft to announce a portable device or for Sony to announce the PS5.