Hi Greg.
I use StrataFrame. Have been seriously doing it now for some months.
I have also purchased MM.NET some 2 years ago, but didn't get to really use it. It might be a problem with me, but I found it a bit more complicated. From VFP, I am a CodeMine user, and I love its pretty solutions and easy to use. This is how I feel about SF now. I have been upgrading a VFP application of mine using SF, and learning .NET through this process. I can say nothing but good things about it. The support team is the best I have known from all times, and I'm not as young as I look. (or at least as I would like to look)
Hope it helps you.
Best.
Ivan