Hi Russell,
VistaDB looks very interesting but one thing I did not like it is that is a file share database, which means that each application instance needs to open the file database in order to access it, pretty much like VFP and I am not sure I want to go back to that kind of database.
On the other hand I did like all other features, specially their compatibility with MS-SQL which mean that it would probably be easier to implement in SF and our applications to switch from VistaDB to MS-SQL with less code change impact.
What I like about MySQL is that it is a real SQL database,portable and lightweight, reliable, and it can also be embedded and it is available in almost every hosting ISP at a very affordable price for everybody.
I have an application using MS-SQL Express and found out that one of the process needed will be importing thousands of records (sometimes 400,000+) and that those records should be keep in the database for comparison with new imports, that hits me very hard, because now the database file is growing up pretty fast and the only option would be to buy the MS-SQL Standard license and it was just unexpected and that would be the case for almost any customer using this application and that could hurt any possible sale. MySQL is very well suited to handle this application requirements but since it is not supported by SF/DDT/BOM/RBS then it would be very hard for me to manage and I use all SF tools in all applications.
Edhy Rijo