There is a limit (from register365) for each domain
1. Combined web and email storage quota cannot be more than 2000MB.
2. Max bandwith qouta - 5 GB
3. Max POP 50
4. A limit of options in the controlpanel.
5. no website for the anonymous webmail
6. no software updates
Still a old version of MySQL -> 4.1
MySQL 4.1 Community Edition
* The current recommended version is MySQL 5.0 Community Edition
* MySQL 4.1 is in its extended support phase. We no longer routinely provide security updates in this location.
* Security fixes for MySQL 4.1 are only made available through the source repo
Conclusion: faster, stabler and a lot of restrictions!