Android has a lot of file managers, many of them offering more power to what is already a power tool. But they say beauty is in the eye of the beholder and those file managers do not always meet the aesthetic taste buds of some users. Those users might want to give these two updated file managers a whirl, as they offer some superpower but look nice to boot, thanks to a dash of Material Design.
Of the two, Cabinet Beta is more representative of Google's new design language even at first glance. That's in part to the use of the almost iconic blue and pink color scheme that seems to be used for most of the Material Design examples. But even beyond the colors you immediately get a feel of the paper and pen metaphor prescribed in Material Design, especially with the presence of the floating button for adding files and folders. Cabinet Beta, however, isn't all show. It doesn't come with all the bells and whistles that more powerful file managers boast of, but it has enough to get things done: root access, SFTP, quick folder shortcuts, and an easy multi-select feature enabled by tapping on the file or folder's icon. As a bonus, Cabinet is also open source software.
Sliding Explorer has a longer list of features but might give off a less than Material feel. That said, it shares many of the design features of Cabinet, like multi-select via icon previews. Sliding Explorer shares many of the same features, including root access and a way to mark folders as favorites in the slide out side panel. However, it does add some interesting features, like handling of ZIP files, cloud printing (Android 4.4 and above), and even DashClock extension.
Both file managers focus on simplicity without getting bogged down with too many options, and so it isn't surprising to see a dearth of configuration options in the apps' settings. That said, that might actually appeal to some segment of the Android community. For those who do hear the call of these file managers but would rather not have any Material flavor, they do allow for minor tweaks, like switching to a dark theme and turning off status and navigation bar translucency, to give the apps a less Andorid L look.