I don't think you will regret your choice of the Quattro.
I have purchased from KellyCo ("New" Garrett GTAx550), Surfscanner Detectors ("New" Headhunter Diver/Mr. Bill a #1 dealer and great guy and big sponser of this site ) and Backwoods Detector Sales ("Used" Quattro/ "Factory floor model Garret Infinium LS/Richardntn he is always on this forum site)Richard does not sell Minelab but always seems to have a line on certain models. The largest dealers could not beat Richards price on the Infinium, but I lucked into this deal. All of these have been purchased in the last couple years. Why so many, I travel alot and differant detectors work better in certain areas, but nothing travels better than a Detector Pro model. I stayed away from the private sale but some good deals were listed in the classifieds. If you choose that route go to the feedback forum and do a search. I did this for Richard. Richard did give me the names of people has dealt with and the feedback was good.
All of these dealers large and small have been great to deal with. The one thing I did get with the small dealers is that personal call or e-mail to follow up on my detector purchase. Also they read your posts and follow up with you if you are having questions about the operation of a unit. I have heard the same about KellyCo but have not experienced it myself.
I spent a bit of time shopping around for deals and it paid off. It is tough to find prices cheaper than KellyCo.
Do your homework asks questions but a KellyCo purchase is a no brainer.
Good Luck!