Both are mild paint cleaners that lay down some protection (assuming you mean 1Z Metallic Polish) and leave the paint looking very wet. VM is a bit more versatile since you can use it on practically anything. A bit wetter looking too, IMO.
Enough said above but I will add that VM is an absolute killer product to use by rotary. Takes care of light buffer trails and leaves an awesome finish behind. Follow that with a nice wax and stand back and enjoy!