>I am only interested in opinions from a stability point of
>view.
>
>Is it now worth moving to VFP6 with SP3 ?

I've done a small new app in vfp6, which I'm pleased with. I'm in the same situation as you with regard to a very large, extremely stable vfp5 SP3 app. I plan to move it to 6 SP3 soon, but I'm going to do it gradually in parallel, on a test server, first with test data, then with a few users accessing real data, sort of beta-style, a step at a time, until I'm 100% sure all is well, then a full replace...that's my plan, if that's any help...