Walter,
I am not knocking VFP or its grids but what you say about .Net grids really does depend on the implementation of the grid you are using. If you go look at the following link you will see lots of features that VFP will never support. If you download the sample you will also see that optimisation is core to the design of this component, look at the statement made about grouping.
We have chose this grid for our next generation of products.
http://www.syncfusion.com/products/gridRegards
Neil