I tried lot of VU meters before I found this one. I don't have any other plugins from PSP, but this one is good. Use it on every track in FL Studio. On front side you can change type of metering (VU or PPM /Peak/) by simply click on the switch. The meters have an adjustable integration time (300ms), but you can change it by click on "PSP VintageMeter" label. You can also change 0VU Refernce level, PPM integration time, PPM return time, Meter delay and Overload counter. CPU usage is near zero for this plugin.
GUI would be a little bigger for me but regardless of this is PSP VintageMeter the best VU meter here.