Hello Anna,
I current work with both VFP and Delphi. Yes, Delphi is faster in loading forms but the difference is not so important, and if your form must OPEN some tables (only open !), it drammatically slow the loading time.
Delphi is better language, have a better debugger, have better compiler and is more flexible than VFP, but VFP is much-much more simple to use, configure and install (on customers PC) and it is very much powerful on database.
My little suggestion is: leave your app in VFP !

Sorry for my poor english

Ciao
Bruno