Previously, I have used geodatabases as an easy way to keep all files together rather than having dozens of shapefiles all over the place, and it is easier when finally exporting all the relevant data to the client.
Why should I use a geodatabase instead of shapefiles when analysing and running functions on my data?
My primary focus is within ArcGIS, I don't usually edit outside of that environment.
This question is related to How does Personal Geodatabase work from Microsoft Access perspective?
Best Answer
At a high level, it might be preferable to make a choice based on whether users are inexperienced and need nothing more than points, lines and polygons. Shapefiles could be suitable for this.
If they need annotation, domains for pick lists and validation, raster, longer field names, etc then File Geodatabases could be used which are easy to use, fast and can be massive in size.
Personal Geodatabases are based on MS Access. Unless there is a requirement for Access users to also interact with them, there is more restriction with this choice. The 2Gb size limit & inability to store rasters is restrictive.