Ember is promoted as a combination of a screen/web capture utility and an image catalog. It does the former adequately, but not as well as other options that are free or much less expensive. The latter function, however, it completely fails at. The available options for organizing your stored items are fewer than in the now out-of-date version of iPhoto that came with my Mac. The only thing it does that I've not seen in other apps is the arrange by dominant color function, but that's hardly worth $50. Everything else it does, I can accomplish as well or better with Evernote, GraphicConverter, and Captur, for $10 less total. (Plus I already have those apps.)
The worst thing about Ember, though, isn't in using it—it's behind the scenes. Whether by design or bug, it does not remove files from its storage space in ~/Library when you delete them from within the app. I discovered this after testing it by importing several images from my collection, then deleting them from the app's catalog after determining that it did not meet my needs. The next day, I discovered that my available disk space had dropped by nearly 20 gigabytes (which is far greater than the amount of space normally taken by the set of images I tested with). A disk sweep showed all of that as being in Ember's library folder, which still contained all the images I had told it to delete! This is inexcusable.
To boot, the app makes itself very hard to uninstall. Even with an uninstall app like AppDelete, Ember left a launch agent behind—and even after I moved that agent to the Trash and restarted so that it wasn't running, it still relaunched itself *from the Trash* and began a cycle of launch-crash-launch-crash (because the app's components were no longer installed) that did not end until after I emptied the Trash (which was possible only by the Finder catching that agent between launches so it could be deleted).
I'll give it two stars only because it does an adequate (but unimpressive) job of capturing. In every other way, this app is abysmal and barely even deserves one star. Even in a bundle, it's not worth anything.