We've been working on a FileMaker project recently where there is a requirement for tracking changes made to the data, so that at any given point in time, you can look at a log of who changed a particular value and when it was changed. In 4th Dimension (and many other database environments) this would be done in database engine level triggers, but FileMaker does not have this feature.
Each of these has advantages and disadvantages.
The auto-enter calculation method is free, but will not capture data changes made through imports or scripts, it only captures changes made on layouts. It does work with FileMaker Go, but does not allow data modifications to be rolled back.
CNS Audit is fairly reasonably priced, but we've found that it imposes significant performance penalties given the user interface design we are using (it is slow when there are more than a few portals). In addition, it does not work with FileMaker Go or Instant Web Publishing.
SyncDek looks like a good solution and I really like the fact that it is server based, not client based. It is compatible with FileMaker Go and allows rollbacks. However, SyncDek is a fairly expensive option and at this point is outside the budget for this project.
If any readers out there have suggestions for alternative solutions to this requirement please drop us a note.