I'm in 2 minds about this. I've always loved the philosophy Nokia (or Microsoft now I guess) take towards cameras on phones, and I hope by now they've been able to refine the Pureview technology (and hopefully sort out the OIS which was pretty poor in the 1020 IMO) so that it's near perfection. I mean obviously right now it's difficult to take the camera samples seriously because it's Microsoft reps showing off promotional photos. I have faith in them though, and I believe the camera will be class leading.
However, I'm seriously not convinced by Windows Phone OS in the slightest. I have an 808, which I got because the camera on my M8 is pants. The 808 is cheap and fairly small, so I have no qualms carrying both devices at the same time. With the 950/XL being flagships, it's going to be difficult justifying buying one of these solely for the camera, so I'd have to use it as a daily driver, which I don't think will be an enjoyable experience, as I really love the near limitless customisation options on Android, especially with a custom ROM.