I recomend to check this article and send your opinions.

MySQL vs. the Lite Databases: A Fair Comparison?
By Lisa Vaas

Opinion: Not to pick on MySQL or anything, but does it really makes sense to compare it to the light versions of proprietary databases? I thought not, but MySQL users say I'm all wet.

Not to pick on MySQL—I'm glad to see they were picked to be editor's choice in Builder AU's recent road test of databases, which compared MySQL, SQL Server Express, DB2 Express and Oracle 10g Standard Edition.

"Release 5.0 of MySQL is really taking it to…Oracle and DB2 with advanced features such as cluster support and fault tolerance, and in most other departments the features run head to head with the competition," the review reads. "MySQL V5.0 is a compelling product and it is hard to argue against its nomination for the Editor's Choice award."

But is the premise of the review actually sound? For the purpose of comparing MySQL to the "lite" versions of the proprietary databases, Builder AU created a hypothetical online business, relatively small, that sells books and DVDs.

The business needs to grow, so it needs a database that can scale from a dual processor or four-way server on up to a small server farm.

As a colleague pointed out to me, the premise appears wobbly, given that the express database versions are meant to be marketing tools or to be used as embedded databases for certain applications.

The databases are hobbled for a purpose: They're just there to give people a taste, in hopes that they'll go on to upgrade to full-scale versions.

A Microsoft spokesperson put it this way. There are three target audiences for SQL Server Express: nonprofessionals, including students and enthusiasts, whom Redmond hopes to hook early and often and to infuse with SQL Server 2005-compatible skills they'll take into the job marketplace; ISVs, for use in light applications, trial versions, desktop applications, and/or distributed applications with many low-scale databases replicating back to a central hub (hub and spoke) such as retail/branch scenarios; and within companies, for the same types of situations as the ISVs face.

Full article : http://www.eweek.com/article2/0,1895,1906913,00.asp