VU / PPM meters mimic the behaviour of "analog" meters, and I think they show average power. A "wire and magnets" analog meter has no chance of responding to high frequency, short time period transients. This accounts for the "Rule of thumb" when using analog recording devices that, whilst you can set a bass drum record level to peak near 0db, it is best to set a cymbal record level to more like -10db because the meter cannot respond fast enough.

It's different for digital / computer work.

I would always use an LED style "peak hold" meter; by its nature digital recording will emphasise any clipping and the peak meter gives you the best chance of spotting it.