Good that the new tool Office Web Apps - Access 2013 might be a solution for the users who is looking to save the data in lists which are highly relational. But, before you considering to go or not to go to Office Web Apps - Access 2013 below are the observations you should check. Online I didn't find any limitations document/articles from Microsoft to give you the stats, boundaries etc, but below are the observations from my expertise.
- Access 2013 has the capability of creating them and publish to Office 365. (It's available in Access 2010 as well but I see there are new templates with additional built-in features.)
- The backend server they use is SQL Server 2012 and it has good capabilities compared to previous versions.
- You can package your App to publish to Microsoft App market place.
- Security can be added to the access database with the help of SharePoint groups.
- Of course, they support relational data.
- We can't use the SharePoint workflows in Access Web Apps.
- If you have existing database then you can't use Access Web App as a front-end to host the UI for existing database.
- You can't define the permission levels in Access Web Apps like who can only add records or who can only edit records on a particular table. If a user can edit records in one table which means they can edit all tables in the app.
As my understanding there are some issues in using Access Web Apps. The recommendation from my side is if you have a requirement where you need to provide a form to user, collect data and show small reports then this solution works good, (which means for very simple databases). But, if you have complex design/tables with business data then this is not be the right solution (medium or large databases).