To this day I use it for VJ work and it always gets rave reviews.
With the OSS project I've been able to build a great workflow for previewing and picking the best patterns for my aesthetic.
If I had one feature request it would be a way to take a set of patterns and an MP3 file and render an output video faster than real-time. It's much easier to use pre-rendered videos and tempo adjust them in VJ software than doing live rendering.
Edit: GH Issue discussing rendering: https://github.com/projectM-visualizer/projectm/issues/205