Spoke too soon. When I actually got to trying the charts out, they need supporting libraries from other sites. I was several layers into other sites and finally gave up. As far as their appearance, they are really nice and they can be dynamic; meaning that they can be made to change as new data is available. They support tooltips that expand data when you hover over the data points, zooming in on certain areas, and many other nice features.
I just don't see how they can work well with an isolated arduino in the middle of nowhere.
One notable thing was that the forum and example they provide didn't have a clear example of how to actually get data from some repository and display it on the screen as a graph. Yes, they have examples, and offer them up to be examined by jsFiddle, but the dynamic and repository examples don't work in jsFiddle (at least I couldn't get them to)
Nice set of tools if you want to spend a week or two diving into the API and experimenting to get it right, but they don't seem to fit the bill for way far away devices that aren't big web servers.