Bento is simple database solution introduced to the FileMaker family to try and get peoples feet wet. This will work well for tracking data but doesnt have alot of the power you will find in FMP. I havnt used Go yet but im going to look at creating a "Lite" version of my database solution for it. Bento simply couldnt keep track of everything i needed and manage relationship or create a custom userinterface.
Many of these features may be missing with Go, as it is a mobile solution for FMP.
If your comfortable with relationships and done some design in the past id get FMP and GO. If not Bento will have you tracking data in no time.