I thought the harmonizer in the G-70/Discover5/E-80 was REALLY good, on par with the Korg TC Helicon units. The only unit from Yamaha i've ever tried was the VH2 and i didn't like the way it sounded but it tracked pretty well.
VH2 is horrible when tracking no matter how your set it up....
try a trio or whatever and come in to the mic side ways or anything outside of straight dead on as if you were performing live to the mic
drop outs occur all the time and the quality is cheesy at best.
Sorry all you yammy players but that's my experiences, ...until someone demos VH2 and proves me wrong I'll stay with that fact on VH2. At least korg got it right and asked TC helicon for help on their models...