OCS doesn't currently support either the import/export functionality or the 'expedite submission' features that are included with OJS, but they will be added over time. Specifically, back-porting OJS' native import/export functions is a high priority for us, and this would go a long way towards providing the functionality you are looking for. I would advise signing up for notifications on the following bug: http://pkp.sfu.ca/bugzilla/show_bug.cgi?id=3261
You can expect to see some work on this front in the near future.
In the meantime, I would suggest you take a look at OCS and evaluate the features that don't necessarily have to do with conference management per se, and see if they add enough extra functionality for it to be worth your while. In particular, I would investigate the Reading Tools component, options for metadata harvesting and dissemination, and the management and display options. As well, it may be worth evaluating whether or not you may move to OCS' conference management components gradually, as has been the case with several journals that I'm aware of.
If you have any other particular questions, please let me know.