CDISC has an excellent ODM Certification system. As one of the developers of different versions of the standard, and as an independent consultant, I regularly help (EDC) vendors with getting their systems certified.
One of the questions that comes back over again is about the difference between "snapshot" and "transactional" for import of metadata only (columns 1 and 3 of the table of the certification webpage). I recently had a chat with Dave Iberson-Hurst (who is doing the certification testings) and he told me there isn't a difference:
"The Transactional metadata import is no different from the Snapshot metadata import. It is an implication of the table layout because it is there for data import. In theory there is nothing in the spec to say the FileType attribute should be set to snapshot or transactional for a metadata import so you could set it to either, I would use snapshot but some people dont. So if you tick one of the boxes you tick both".