I'm not going to vote yet, and perhaps I shouldn't since I've never owned the OG Xbox and only played on it very rarely in terms of titles or at someone else's house.
OG Xbox seems like the best system, though. It had online multiplayer back in the day that was revolutionary, it had the Star Wars KOTOR games (two of my faves), Halo was beloved, and it got a lot of third-party support as well (at least from North America and Europe).
I got a Wii U brand new in 2014, and I got a Vita 1000 used in 2021. Wii U clearly has the better first-party lineup, but Vita probably has the better third-party lineup. Stardew Valley (at least the PS4 and Switch up-to date releases) is my favorite game ever, and it's available on Vita (it was cancelled for Wii U). Vita also has better online and used to have a lot of functioning apps, PS Plus monthly games, etc. And to this day, it has Remote Play (with PS4 and a tiny amount of PS3 games) even if it's the least capable device in horsepower for it.
I might post more on this thread later, but my initial (potentially cop-out) answer is...
Xbox probably is the best even though I don't own one.
Wii U probably has the best exclusives (at least before many were ported to Switch)
Vita is a sleeker little device than the Wii U and the low specs can be forgiven since it's a handheld.
Lifetime Sales Predictions
Switch: 161 million (was 73 million, then 96 million, then 113 million, then 125 million, then 144 million, then 151 million, then 156 million)
PS5: 122 million (was 105 million, then 115 million) Xbox Series X/S: 38 million (was 60 million, then 67 million, then 57 million. then 48 million. then 40 million)
Switch 2: 120 million (was 116 million)
PS4: 120 mil (was 100 then 130 million, then 122 million) Xbox One: 51 mil (was 50 then 55 mil)
3DS: 75.5 mil (was 73, then 77 million)
"Let go your earthly tether, enter the void, empty and become wind." - Guru Laghima
