For research purposes what vacuum pump do people personally think is better and im not referrin to the hand pump but the automatic. Units i dont understand them very well been tryn to research as much as i can but still a bit puzzled at which is the best bang for ur buck....i have a buddy using the rocker 500 unit but i havent seen it nor know exactly how it works or benefits over a hand pump other than having to pump it every so often bc it does the work for u on that end..... Sorry if this seems confusin or jumbled thanks guys