Heard good thing about the Canon G1-X.
I can personally vouch for the RX100, particularly for Disney.
In fact, the RX100 can in many situations, produce better image quality than a basic dSLR with basic kit lens. (As the RX100 has a lens that is better than a dSLR kit lens).
In terms of landscapes, the RX100 really shine. It can handle Disney dark rides. Works great combined with a gorillapod -- a great compact portable low light/fireworks set up.
It's focus is reasonably fast.
Where it doesn't match a dSLR -- you have less control of background blur than a dSLR. And the lens is limited to a range of 28-100mm. This is slightly more than most dSLR kit lenses, but you can always add another lens to a dSLR.
In terms of old RX100 versus newer. Image quality is almost identical. The older is a bit more compact, and much cheaper. The newer version has a hotshoe (if you want to add external flash or EVF), tilting LCD, and wifi. If you don't need those things, I would save money and get the cheaper version.
For $400-$500, I actually say the RX100 is a good value.
As it is close to your budget, I might glance at the RX10.
Same sensor as the RX100. But the key difference is a 24-200 2.8 lens. In perspective, there is no such thing as a 24-200 2.8 lens for dSLR. You would need to get a 24-70 2.8 ($500-$1000 minimum) and a 70-200/2.8 ($1000-$2000 easily).
So it's the RX100, with an even better lens. The lens is wider than the RX100, and has double the telephoto reach.
The RX100 lens is slightly faster at the wide end (1.8 versus 2.8), but the aperture only reaches 1.8 at 28mm. Zoom in to 50mm or 100mm, and the RX100 aperture shrinks quickly. The RX100 stays at 2.8.
Meaning -- extreme low light, Disney dark rides -- you may be best served with the RX100 at 28mm and 1.8. But in regular low light situations, where you might want freedom to zoom a bit, the RX10 will be far superior. The RX10 also will give you better control over background blur (still not quite as much as a dSLR, but better than any other bridge camera).
The RX100 is a great sometimes dSLR replacement for advanced photographers, and a possible every day camera for basic needs. The RX10 is potentially a full time dSLR replacement even for some enthusiasts.