Kevin says:

@Sim2K - one of my clients has just approved the funding necessary to add registration form support to the form and related plugin family. So that should be out in September.

I see Jeroen's plugin as a quick option for people needing a simple profile form solution. The form and related family of plugins has many more features (and so has more of a learning curve, of course).

...so I'll probably stick to Flexprofile - registration form support will be a great addition...