A lot of Zen templates are based on the default one which isn't the most awe inspiring template out there, though there are some very good ones available that make it difficult to tell that it's a Zen store at first glance.

I don't think you'll have too many difficulties importing your stock from Zen to Magento when it's finished. They are going to want to build their userbase very quickly, and with their initial target market being other OS cart users, they are obviously going to target pre-existing Zen, OSC and CRELoaded users, so the obvious way to do this will be to make it easy for them to import their inventory from their current stores.

If they don't create a DB importer from Zen to Magento, you can guarantee that someone else will.

__________________
Lawrence