Mike,

Since I am doing this right now, it depends on the functionality required.

I am using the MMframework and I am able to create forms that are maintenance forms in the same speed as I was able to in FoxPro - If not Faster in .NET.
Building the Business object for the form is a little slower if it is complex, but a simple return data from a single table from SQL server, done in a few seconds.

More complex stuff, well, I haven't learnt all the capabilities of the framework, this is my biggest issue, I keep saying, I used to do this in VFP, how can I do it here, where do I find something similar.

Otherwise once you get past that learning curve you should be flying.