>>Keep in mind that some of the three months was spent leaning and figuring out how WPF works. Once yhou get experience with it, you can develop apps much more quickly.

My hearing is weak at best, but I thought I heard him say that 3 people worked 4 months and that they're a little over half done.
I also that I heard him say that they spent time trying to devise new ways to use WPF, but I didn't hear him talk about learning WPF. That's R&D.. not learning - and if 3 experienced WIN Form developers of Hollis' caliber invested that kind of R&D time into what's bascially an order entry system which matches demand with available resources, the WIN Form results might also be pretty striking.

If he tries to devise yet more new things with his next WPF app, it might take less time or more time, depending on how far he stretches and how lucky he is.