I have the Red Devil XTX. It's a superb card, and for now, it pushes all games way beyond what I want/need in games. Moreover, the cooling is excellent, it overclocks very well (flirting with stock 4090 in rasterization), and runs cool. I've also owned a 4080, and the experience is largely equivalent, but the XTX takes a non-trivial edge when overclocked (except in RT, of course). It's not a huge lead for the XTX, but noticeable in taxing games. Drivers and stability are effectively equivalent between the two cards in my experience.
As for whether a 4090 is worth the extra ~40% in cost over the 7900 XTX (if you can find them for those relative prices).... sort of, and it depends. If you plan on holding onto the card for 2-3 years, I'd say go for it. The longer you hold onto a card, the better the investment, and in 2-3 years you'll likely want the extra horsepower the 4090 provides. However, if you want a great card now for the next 1-2 years and plan on upgrading with the next gen or refreshes e.g. I tend to trade up when there's a refresh (likely the 4080 ti, when it becomes avaialble), go with the XTX. The 4080 is a hard sell since it's largely equivalent to the 7090 XTX in my view, but it costs ~$200 more.
One caveat, if you are ok running DLSS, nV has the obvious example. For me, I refuse to run with DLSS or FSR: it's one of those thing's that is very obvious when you know what it looks like -- and it's an unnoticiable distraction. I'd rather run "clean" and turn down settings a bit.
In fairness - the $999 XTX does not exist, really. It is faulty and not worth the investment (AMD reference models whether they're AMD or branded by PowerColor, MSI, etc.). You need to get an AIB model and in most cases that is an extra $50-$100 or more (Red Devil LE is $1099.99).
So - it's really just $100 more to go RTX 4080 from 7900 XTX.