For me it has to be the XL Pro which I still own. With its simplicity, accuracy (separation of targets) and depth on targets. My best find with the XL Pro was a small gold heart shaped with a center pearl and small chain attached at almost 9 inches below the surface! You just have to watch that twitchy needle when P.P.
My first White's I bought was in 1977 and it was the 5000/D (blue box) which is probably the flagship where it all began. Both XL Pro and 5000's, 6000's both run at 6.592 kHz. I use to own an MXT and really liked it.
Back in 2009, I bought a VISION and I said to myself, Oh My! What did I get myself into. What a learning curve! ...But what a powerful detector. "#1 Leatherneck" summed it up for all and myself, thanks Guy. Next I bought a V3 and presently have a V3i. Man, I really like the flexibility of programing, the 3 simultaneously hunting freq. and separate freq. if you so desired! The one feature that I mastered is the "Bottlecap Reject" setting. Once I got accustomed to it, my take in quarters increased and bottle caps decreased. These are my top picks.
TC-NM