I think I get the difference between these.
1: phasor~ can run a loop over and over again. There can be issues when the file returns to the beginning though.
2: vline~, I think, has a delay, which does not occur with phasor~. I am really not sure with that one.
When I learned to use pd, I assume I was taught to use phasor~ with a hanning window to avoid digital clicks in audio file playback. I started to use phasor~ with hanning windows to fade in and fade out audio files as well.
However, I have been dabbling in using vline~ as well. In fact, I started to use vline~ with a hanning window as well which seems to work well.
Are there reasons to go with one of the other in various situations? Any advice would be greatly appreciated.