Oracle Express Edition and MS SQL Server Express Edition

Today I was listening to a course from the dark side ;) One quite small fact (I was not aware of) about SQL Server 2005 Express Edition compared to Oracle 10g XE caught my attention though.
These versions are similar in their limitations i.e.

• 1 CPU
• 1 GB RAM
• 4 GB user data

But there is one difference not in favour of Oracle - for SQL Server Express Edition one can create up to 16 instances on a single box, but for Oracle XE only one. Of course in general it is not the main decisive factor to choose between SQL Server and Oracle, but I can imagine some scenarios where more than one instance of Oracle XE on a single box would be nice, for example, simultaneous development of different applications on XE.