I can't figure out much of anything from the links so far. Is this like MS Access, or Outlook, or Journaler, Numbers with forms, or what?
It's like Filemaker "light" for consumers
iApps like the integrated iCal, address book, mail, safari, etc. seems to already do everything that bento does. What functionality does it provide that the iApps don't?
It doesn't have i at the front, that's a small blessing right there. But more importantly, it's not a mail/calendar/address book; it's a database with a GUI.
Which, obviously, is exactly what the iApps are, really. But if this is like it's daddy Filemaker, then I would guess that the database part is much more emphasized; You can probably control GUI to some extent based on what's in the Database and what info you want to highlight, like Filemaker.
Chances are it has templates, and you can say, give me an "events" template, and it will go and find all the appropriate database items and populate the events, and then you can say, I don't want the "location" field but I DO want the "phone number" field, and it will adjust accordingly.
Probably you can create your own templates too, like a shortlist of cars you're considering buying, narrowing it down to, for example, cars under $40k with standard MP3 player, all-wheel drive and alloy tires, assuming you have entered the info in your database.