Hola Lobo2024
Capacidades de SQL Server Express Edition:
http://msdn.microsoft.com/en-us/libr...sseover_topic3
Revisa:
Engine Specifications
The 4 GB database size limit applies only to data files and not to log files. However, there are no limits to the number of databases that can be attached to the server. There are some minor changes to the startup of SQL Server Express. User databases are not automatically started, and the distributed Transaction Coordinator is not automatically initialized. For the user experience, though, there should be no difference other than a faster startup. Programmers intending to use SQL Server Express are recommended to keep these changes in mind when designing their applications.
En cuanto a escalabilidad, no tienes problemas para subirte a un PERSONAL EDITION (uso personal, no en produccion), DEVELOPER (ambiente de desarrollo), ENTERPRISE o COMPACT (Mobile)
Saludos