3DMark came out a while back to give your Android device's GPU a rating, and now Futuremark's other benchmarking tool has arrived in the Play Store. PCMark will analyze the overall performance of your phone or tablet, rather than focusing on individual components. At the end you get a number. Is that number useful? Maybe.
After installing PCMark (yes, the name doesn't make as much sense now) you will still need to download the 400MB test file. When the necessary data has been obtained, PCMark will offer work performance and work battery life tests. More types of tests are on the way apparently, but this is all we've got for now. The work test looks at things like web browsing, document editing, photo editing, and more. Note, you need at least 80% battery to run the work battery life test (what is this, a Moto 360 update?).
It looks like PCMark is placing mostly Tegra and devices at the top of the list, with an assortment of Snapdragon 801 and Exynos mixed in. The gap separating all modern processors seems very narrow, though.