I just checked out this CMS, dont knot much about it. But i noticed that 4.1 is just out in Alpha version, usually there is Beta and Then RC versions coming out until the production ready version. Usually this takes 3 months to a Year depending on the number of developers and testers available in a project.
4.0.1 to 4.1 should be a pretty easy upgrade, so if you'll go live before march I'll highly recommend using a stable version so you don't have to downgrade or wait because ezp doesn't come out when you 'hoped' it would
