Does anyone know the performance of 4.4.1 running with SQL Express? I want to demonstrate it to another organization and need to know if its performance with SQL Express is going to hinder my efforts. I plan to configure the web site locally and when done FTP it to a source outside our firewall, database and all. I've done this successfully in a lab environment. I need to know how many connections it can handle.

I don't think SQL 2005 Express has a limit in the number of connections like MSDE used to.  Microsoft decided to put limits on the resources it can use instead.  For instance, it will only use 1 CPU, only 1GB of Ram, and a maximum size for the databases of 4GB.  The actual database engine is the same as the full version and should perform like the full version within the constrains above.  See more about it here: http://www.microsoft.com/sql/editions/express/default.mspx

Carlos