I've generally held PlayStation and Nintendo (both handheld and home console) as essential to my gaming ecosystem.
I've generally enjoyed Xbox platforms. OG Xbox through the first year and a half of Xbox 360 was probably my strongest interest in the ecosystem, but once I encountered a few hardware malfunctions with the Xbox 360 (2 RRODs, 1 dead disc drive), my view of the platform soured, though I stayed committed because it was the "main" console that a lot of my friends played during that generation, and it was a point in my life where I had time to spare for frequent online gaming.
That said, I've personally come around on Xbox again in the current moment, mostly because I really like the Xbox One X hardware, the Elite controller hardware, their backwards compatibility support, and the Game Pass service. I currently play as many games as I can on my Xbox over anything else, with the exception often going to Switch if it's a type of game that I can play at decently-matched graphical fidelity as other platforms, for the benefit of portable play, which tends to frequently apply to indie games, for example — it might not be hitting native 4K like the Xbox One X but they often don't have to pare back visual elements and they tend to run well on the Switch anyway.
Prior to the Xbox One X launch, I was VERY into the PlayStation 4 ecosystem. Historically, I've loved PlayStation exclusive titles since the very first PlayStation and I tend to regard that catalogue just as high as Nintendo's first-party and partner-studio output, hence my historical essential status for both PlayStation and Nintendo. My physical catalogue of PS4 games at its peak was (and still is, even though I've sold off some games) the most physical games I've ever owned in my entire life for a single platform — I had over 80 physical games and maybe 30 or so digital titles too, not including any of the PlayStation Plus games I've accumulated over the years.
In this current moment, I still think Xbox's biggest ecosystem flaw is that its exclusives are generally not that compelling. I enjoy a lot of their exclusives but very few of them resonate with me on the same level as PlayStation or Nintendo. That said, I still play a ton of third-party games, and the rise of the indie developer marketplace has only expanded my interest in third-party games, so the Xbox One X tends to generally serve as a very good machine for me to play the vast majority of my games on and it's what I perceive as my current primary platform. Game Pass has just the right type of curation to its catalogue that I feel like I also get a good amount of positive discoverability out of it, too. In addition to that, the history that Xbox has with backwards compatibility support now gives me confidence that my digital library carries forward to future Xbox platforms almost seamlessly, so unlike the past, I won't feel obligated to hang onto my old Xbox just to play those games... and that's genuinely appealing to me, as someone who actually doesn't own any physical Xbox games. PS4 is likely my last physical game platform — I went all digital on both Switch and Xbox One X.
I'll probably be committed a bit more to Xbox at the outset of next-gen, but I still see PlayStation as essential to my gaming ecosystem so I will also need a PS5 at some point. But I can wait on PS5 until there's a few exclusives I know I can buy alongside the console, as it will likely be an exclusives-only platform for me going forward.
Actual real-world performance differences between Xbox Series X and PS5 will be a point of interest to me, as well as how PS5's backwards compatibility support performs in real-world, too. I know Sony has said "overwhelming majority" which I do feel confident about, but unlike Xbox, I've yet to feel that they're as committed — they made some small efforts to bring old games from past PlayStation platforms to PS4, but it always felt like they stopped shy of ever making it a truly great selection. I know Xbox isn't 100%, but I feel like the overwhelming majority of games from the past that are huge hits are available, and I get more of an impression that they will make more of an effort than Sony has to preserve that level of access to their past library of games in perpetuity as the Xbox ecosystem moves forward... but I suppose Sony has an entire generation coming up to prove that they can make the effort too.
Bit of a shame, too, because Sony truly has an absolutely incredible and long-reaching stable of games across all their platforms that they seem to have either the incapability (for business OR technical reasons) or disinterest in pursuing. If PS4 had made an effort like Xbox One did of reaching as far back as possible, there'd be no question about my ongoing loyalty to PlayStation over Xbox.
tl;dr Traditionally loyal to both PlayStation and Nintendo, but now currently in a young phase of being Xbox-focused (though loyalty to PlayStation and Nintendo will be maintained for access to their respective libraries of exclusives).