A Rule that has always served me well in buying a new console is "Three Great Games" / "Three Must Have Games".
It has kept me from a few questionable purchases, and the times I have gone against the rule, I have regretted it and ended up with a system collecting dust.
For the Xbone, for me, I kind of skirted the rule a bit. I wanted the upgraded Borderlands Handsome Collection (though all those games were on the 360), the Rare Replay set, Defense Grid 2, and Killer Instinct. I also was curious about Doom and Mortal Kombat X (especially after they dropped the 360 / PS3 version).
Initially, I was very disappointed. The lack of playable demos is a HUGE step backwards from the 360.
But that said, the number of available download games (as mentioned above, the ACA Neo series is amazing) has made this a very good system to have.
It's all about what you like. I don't do online gaming or have a Gold account, so a lot of what comes out just passes me by. Or is too hard since I'm old (Cuphead! Though this game is still entertaining, I just play the first few levels on the easiest setting, and if I fail to progress oh well, sure looks great).
But back to my main rule, I recommend making sure there are Three games you're basically dying to get your hands on for it before buying a new system.
It has so far kept me from the Switch; I'd love to play Arms and Ultimate Street Fighter, but nothing else really tags me. Plus Capcom's releasing a big SF Anniversary in May that ought to keep me happy (finally SFAlpha 2 for a system more modern than the Saturn!).