[sql-server] Limitations of SQL Server Express

My hosting provider (Rackspace) is offering a fully managed dedicated server with SQL Server Web version () installed. My company handles web development, and has about 20+ clients using ASP.Net + SQL Server 2005.

I am thinking of cutting down costs by installing the free SQL Server 2008 Express instead. I am aware of the 1GB RAM and 4GB/database (is that correct?) limitations. What I would like to know is:

1. Is there any limit to the NUMBER of databases I can install with the express edition?
2. Are there any other limitations I should be wary of? I am a bit concerned about having to set up the database backup - with the express edition it might a lot more difficult.
3. Any other advise?

You can't install Integration Services with it. Express does not support Integration Services. So if you want build say SSIS-packages you'll need at least Standard Edition.

See more here.

Another limitation to consider is that SQL Server Express editions go into an idle mode after a period of disuse.

Understanding SQL Express behavior: Idle time resource usage, AUTO_CLOSE and User Instances:

When SQL Express is idle it aggressively trims back the working memory set by writing the cached data back to disk and releasing the memory.

But this is easily worked around: Is there a way to stop SQL Express 2008 from Idling?

You can create user instances and have each app talk to its very own SQL Express.

There is no limit on the number of databases.

It seems like the database size limitation has been increased to 10GB.. good new

http://blogs.msdn.com/b/sqlexpress/archive/2010/04/21/database-size-limit-increased-to-10gb-in-sql-server-2008-r2-express.aspx

If you switch from Web to Express you will no longer be able to use the SQL Server Agent service so you need to set up a different scheduler for maintenance and backups.