Sitebuilders get a bad rap, from being too generic with little or no available modifications, to not being able to move them to another host. Kopage is an intuitive sitebuilder that has enough modification ability to suit most people and can be moved to another host.
Sitebuilders including Kopage can be moved to other hosts but that other webhost has to support the same sitebuilder. So, in the case of Kopage sites, they can be moved but they have to be moved to another host with Kopage. This does limit it somewhat but as for myself, that will not be a deal breaker.