>Can somebody tell me if there is any advantage to migrate from vfp9 to delphi. I don´t know nothing about delphi, a customer said me that it is more powerfull and efficient than vfp9.

We do a lot of work in both VFP and Delphi.

VFP is highly targeted to business database apps.
Data Entry forms, reports, that sort of thing.

If VFP is doing everything you need, then you have selected the right tool for the job.
Don't let a language snob intimidate you.

Delphi is more "general purpose" than VFP.
It is really a lot like C++ in that you can do anything at all.
Delphi code is like 50 times faster than VFP code, and that only matters if you are in some kind of tight calculation loop - the kind we never do in business database apps.

I saw somebody else complain about stability of apps.
In my experience, Delphi apps are really good, at least as stable as VFP apps.
IF they are written well and debugged well.
IF.

However, Delphi can let you get into a lot more trouble than you can in VFP - just like C++ there is no automatic garbage collection.
Also, just like C++, you can get in to really advanced stuff with a lot more opportunity to screw up in subtle ways than you ever can with VFP. You really need to buy some 3rd party tools for advanced debugging support - Eurekalog is a godsend.

I would never move a successful app from VFP to Delphi for the heck of it.
There is no reason to do that. As others have mentioned, neither language is all that popular anymore.
If you are going to move to another language for the heck of it, at least pick something more popular :)

Good Luck!