I own and use both. I find the VM easier by hand as it goes on and off wet, where as the RMG PC by especially dissolves into the paint and hardly needs any removal when PC applied. I have used both under sealants, but think the RMG maybe more sealant friendly as it contains no wax. Both look very good.
VM is a very versatile product, it cleans up paint really nicely by hand or PC, I use the RMG more as a glaze. I wouldnt be without either, but if I had to choose one today it would be probably VM.