In terms of current Mac-compatible database software which some website reviews have said works in a Bento-like fashion,
Records is pretty decent, and you can import/export CSV and arrange a whole bunch of custom field displays to your liking, and create templates from them. It shows up in Mac
software bundle offers every so often for considerably lower than the usual asking price, and you can download a 14-day trial off the website. The storage format is non-proprietary, and each one you create is just simple text in an SQLite database in a folder with a couple of other metadata files, which you can easily backup/copy/share.
I got in a bundle a while back and used to use it for keeping track of my soundtrack CD collection before I just went and started keeping everything in a pseudo-YAML format via
TaskPaper* because that allowed for greater flexibility in specifying exact contents as-is, rather than having to come up with a standard set of fields to fill out and accounting for variability in advance. Maybe one day I'll export to CSV and import everything back into Records to have a nice-looking visually-browseable copy.
iDatabase is pretty similar (though IMHO doesn't have as nice an interface) and I tried a trial of it when I was looking at the developer's website to check out the overall quality of their software to see if I wanted to get a couple of other things of theirs which are currently being offered in a bundle deal I'm considering. The trial is 30 days, and there's an iOS version which you can apparently sync via DropBox and use for on-the-go record browsing/updating, if that's a consideration.
The display in iDatabase is not nearly as flexibly customizable as Records (it seems like you're limited to having everything appear in some kind of default layout, though you can specify fonts and such), but otherwise it works in much the same way and seemed pretty easy to use. Export was a little more non-obvious; it turns out you have to select a database and Ctrl-click to bring up a contextual menu to see the CSV option, rather than using the main file menus. On the plus side, there is a
specific tutorial on importing Bento databases over at the official support site. Again, the storage format seems to be just plain text within SQLite.
Both Records and iDatabase come with a bunch of pre-loaded templates for common stuff like movies and cds. And both of them could use better documentation for their features and how-tos, although there are some faqs on their respective websites (the iDatabase one is not actually on their website, but on a
different support site which for some reason they don't link from their main) for the important usage cases, and it's easy enough to find out what the features do by playing around a bit.
Some reviews with better descriptions and screenshots (ETA: some of these were written some time ago, and several missing features have since been added to their respective apps):
* Which I should note, is not a usage recommendation, since I'm re-purposing that for something it was never actually intended for.
Although it is a pretty good application otherwise, with the ability to fold and hide items one doesn't want to see/edit at the moment and focus on the items one does, and drag and drop rearrangement of folded nodes, with multiple views to compare stuff. Plus a lot of user-contributed scripts and stylesheets, for which you can write your own.
And it has excellent search/tag filters which you can write pretty specifically and save for reuse, if that matters.
I also have
DEVONthink Personal, which I got in yet another bundle, which TBH is probably overkill, but has this cool feature where it can create a virtual index of the contents of your external hard drives, which you can then browse and search through like you were using Spotlight and the Finder.