Are free PMV makers worth it, or should I pay?

Good news: Onset Engine has a free demo, so you can test before buying. Here's the full breakdown:

Free options

Onset Engine Demo - free, with every feature: the full AI pipeline, all 9 presets, every effect, the timeline editing tools, rounds, Vertical, Triptych and DJ Mode. Limitations are on the output: renders are the first minute of the edit, at 720p/30fps with a watermark, DJ Mode sessions stop at 1 minute, and there's no export to Premiere Pro or DaVinci Resolve. You can still watch the whole edit in the app with the song. This is honestly the best way to test if automatic beat-sync editing works for you.

Auto PMV Generator (Python script) - free, automated, but requires Python + FFmpeg setup and command-line knowledge.

DaVinci Resolve - free, professional-grade, but manual: every cut placed by hand (Resolve Studio 20 can mark the beats). A PMV takes many hours.

Paid options

Onset Studio ($79 one-time, no subscription, v1.x updates included) - the only paid version. Renders the whole edit with no watermark, in 1080p or 4K at up to 60fps, exports the timeline to Premiere Pro and DaVinci Resolve, and has unlimited DJ Mode sessions. 1 PC license, with a 2nd on request. A timeline you built in the demo carries over: activate and render again.

Premiere Pro / VEGAS Pro - $23/month for Premiere; VEGAS Pro by subscription or a one-time license. Manual editing: VEGAS Pro's Beat Detection marks the beats, but you still place every cut.

My take: Start with the free demo. Since it has every feature, you can build the exact edit you want before paying anything. If you like what you've made, Studio at $79 is what gets you the whole video without the watermark, in 1080p or 4K, plus the timeline export if you want to polish it in Premiere or Resolve.