From what I understand, the actual stats of the Stadia's tech is pretty solid, though since it's a streaming/cloud gaming service, it is wholly reliant on your connectivity to the internet to actually get going.
PS5's stats also look pretty good, a good jump up from the current gen, so that can be quite promising. Ability for BC of PS4 games is good too.
As for the next Xbox though, there's no actual stats out for it that I know of, though presumably, they will keep to their new idea of keeping BC a major element, and keeping on good faith that it'll also be a good jump.
Overall, kind of a hard thing to judge right now, with what little information is truly out right now. But time will tell, especially with E3 and other adjacent announcements around the corner. Probably just best to keep saving up for awhile before leaning one way or the other.