What I like most about the marinator is that when the meat spends a length of time in the fridge, the vacuum seals in the odors. I also use if for leftovers, does help keep them fresh and again keeps the fridge smelling fresh.
as far as marinating, can't really say it makes a lot of difference, but I have noticed when doing small cuts of meat I notice air bubbles coming out of the meat as it pulls a vacuum.