It gives photos a “clean” look, with crisp, bluish-green shadows and lots of push in the mid-tones.
It essentially squishes the image into the center of the histogram.
VSCO separately offers a line of professional film emulators for Lightroom, called VSCO Film, which I use and have written about extensively and which I highly recommend. If you have a MAC, the installation process will be easier, as I've included an installer that does all the work for you. You can upgrade to the PRO version of the Starter Pack to take full advantage of RAW using my custom camera profiles (as well as unlocking some other useful benefits).
A lot of people have asked me a variation on the question: “Which VSCO Film preset looks like my favorite VSCO Cam preset?
I think this makes these filters much more usable in a professional photography workflow than you could ever achieve inside a mobile app.
While these filters will work on both RAW and JPEG images, I strongly encourage photographers to always shoot RAW (preferably 14-bit).