Generally we would encourage you to use the newer RadCartesianChart (which is part of ChartView)
for any new project development that you are starting now. With the Q1 2013 we have added Legend support. Here
you can find the documentation for that feature and here
you can find our online demos to see it in action.
Additionally you may be interested in the other feature that we introduced in Q1 2013 - the ChartSeriesProvider
. Basically it is an API for specifying how the ChartView should generate series from a given data source. It is suitable for MVVM scenarios.
If you have any other questions, I'll be glad to help.
the Telerik team