I've just finished playing the original Uncharted, and it's a true gem (it's the real successor to RE4, I think; has much of the same vibe, and way better than RE5).
By all reports Uncharted 2 is significantly better, and that's really saying something...
I wouldn't call Uncharted a successor to RE4, as it's a very different kind of game mostly based on taking cover and killing hoards of armed opponents boasting supernatural aim.
I disagree; I've played though both many times, and they have a very similar vibe. Despite the nominal attachment to the RE universe, RE4 has far, far, more "fight off waves of goons" gameplay than it does horror or whatever. Like uncharted, it's essentially a shooting game that puts you on a linear trip through a bunch of beautifully designed set-pieces for the above goon-fighting.
The fact that most of the baddies in RE4 don't have projectile weapons does mean there's less hiding behind cover and more running around, but in stages where many
do have projectile weapons, you actually do a lot of hiding and sniping from cover too (you very quickly die if you don't). Ammo management is a very important part of both games. RE4 mostly doesn't have the platforming, of course.
Both are notable doing a very good job of hiding the linear stage-based nature behind a lot of gorgeous architecture with a unifying sense of a larger map (RE5 falls down badly here -- it doesn't do a good job of setting the stages into a larger whole, so it feels much more constricting, like you're being herded through a bunch of sets).
One very notable difference is that RE4 (and 5) have bosses whereas Uncharted doesn't.
Uncharted does have a better sense of immersion, with the lack of things like a map, inventory, shops ,etc, and has better enemy (and partner) AI.