Ho Moises,

if the installation is done by a system administrator or another IT professional, use another database. If the client installs the software himself or doesn't have a support contract, use VFP.

I use the VFP database when optimizing for low support cost is an important goal. That is, when software is sent out in larger quantities and a relatively low or moderate price. When support cost isn't an issue, I use a SQL server. This is, for instance, the case for virtually all custom software development I've been working on in the past years.