a) There is no feature specifically built into our themes for this purpose, as they all use the native WordPress user functionality. The built in WordPress Export tool does not include user data either, so you may need to use a plugin
such as this in order to do it. To reiterate, this is not a feature of ClassiPress and we do not officially support third party plugins.
b) Each theme includes a .csv importing tool, so technically it is possible to do this. We have had existing customers who did the same thing, moving from ClassiPress to Vantage when it was released. Thanks.
