This can be confusing to decide what route to take. A meter with "true" VU performance needs to meet industry standard specs that were published decades ago. I posted a few papers I've collected over the years (and have a few more as well on my hard drive) in the tech docs:
https://groupdiy.com/threads/vu-meter-articles-docs.85007/
One of the specs involves the physical action of the meter....rise and fall time, overshoot, etc. That is determined by the physical design of the meter movement.
In year 2024 some folks will argue that a mechanical VU meter is totally obsolete and should be consigned to the dustbin of history. I see a point there, but since I grew up in this biz with mechanical VU meters I find them still usable. My viewpoint will likely set off arguments here!
Yes, the VU spec is 80+ years old and comes from a different time in the audio industry compared to now. LED (or similar) meters have taken over the world. One reason...they are far less expensive. Also, the meter "ballistics" can be changed by tweaking the driving circuitry.
El cheapo mechanical "VU" (ahem) meters made by Mechowhung <g> are just eye candy compared to Ye Olde mechanical meters that met/meet the published industry specs. They flip and flop around when driven with a program signal.....I call them "wiggle needles".
Unlike a true mechanical VU meter the cheapos don't have the required internal diodes to convert the audio signal into a DC voltage to drive the meter's movement. No biggie with a card like the JLM which has that option.
I don't know what to suggest for any given project. Over the decades, I became used to a decent VU meter that also had a "peak winkie" LED that detected fast transients which could cause overload/clipping that wouldn't register on the associated mechanical meter.
One overlooked advantage of a CALIBRATED meter is adjusting a signal voltage to a fraction of a dB...useful when calibrating an analog tape machine. Ooops...another obsolete device! lol
Younger folks will scoff at me......shrug.
Bri