I tried lots of Comic Collection software before settling on this. It used to be Windows-only but there is now a Mac port. Because of it's Windows roots, you may find that it behaves more like a Windows app at times than a Mac app.
However, there are tons of customization options in here for tagging your books, showing where they're stored, just about anything you can think of.
This definitely has a developer-designed UI, as you will find tons of options cramed into a few small screens with little description of how or what they do, but it's easy to experiment.
This software was a godsend for me and our local comicon. All I have to do is see which writers or artists are going to be at comicon and then search for their names in the Collectorz software to see which are in my collection.
The software downloads common information from the developer's database (I think they pay Diamond for the data) into your local copy. So when you're adding books, you enter the title or barcode (yes it supports a barcode scanner); it will search and pull up issues, and all you need to do is check off the issues you have. It will bring all the writer, inker, artist, color, character, etc, information into your local copy of the database.
If you buy the pro edition of the software, you can sync this data back up to their cloud storage and show off your collection to your friends. There are also Android and iOS versions of the software which you can synchronize with. The sync stuff could be a bit more behind the scenes, but it gets the job done.
About a year ago, they made an unfortunate change to this software. In addition to purchasing the software, if you want to receive updates you need to start a recurring subscription for 2.50 USD / mo. They have some other bargains like three pre-paid months. When your subscription ends (or is canceled), they do not take the updates back, you just won't get anymore.
Overall, this is good software. I think there's a lot of room for improvement, but as it stands, this is the best I've used.