In some ways this is the single biggest advance in the new version, and in other ways it isn't an advance at all. It's an advance because Capture One was previously very weak in the area of digital assets management, choosing to focus solely on raw developing. Faced with the growing challenge from, among others, Adobe Lightroom, Phase One's acquisition of Media Pro was a smart move — we had done a head to head shoot out of six digital assets management systems a few years before, and Media Pro was the clear winner. From my point of view, the combination of Phase One's rejig of Media Pro and Capture One Pro 6 made for the best possible combination of a lightning fast digital assets management system and an intuitive raw developer that was tailored to professional use.
Bringing the Media Pro features into Capture One means that you can save some cash by not acquiring both systems, and it also means that you can quickly catalogue a shoot and then work on it in Capture One without moving from application to application.
On an older machine (2008 Mac Book Pro) we were able to run Media Pro without any issues of lag at all. On the same machine, we found that a large catalogue of over 50,000 images did not convert properly (after two hours trying). Using small catalogues on a 2013 Mac Book Pro we found that the digital assets management features in Capture One Pro 7 zipped along without difficulty.
Whether you use the new cataloguing features is up to you — Capture One has a Session mode and a Catalogue mode, and you can happily stick with the older Session mode if you prefer. If you want the cataloguing, though, then you can use Capture One in this way, and you have all the functionality of Media Pro without having to buy additional software.
If you're moving across from Lightroom, this may be a deal clincher — Lightroom's principal advantage of Capture One was that it did all of the databasing functions as well as raw development. Now Capture One does it too.