I like them both. The Vaquero does have the pushbutton mode change to make it quick to size & shape and pinpoint if you're hunting in the Disc. mode. But the Eldorado has a mode-select toggle that allows you to select your search mode, All Metal or Discriminate, and then toggle to the other to check a signal.
They are both advertised as having ED-180 discrimination, and I know the Eldorado does, but will have to double check a Vaquero. My friend's Eldorado worked better than a Dealer's Cibola I compared to last week because the Disc. mode did adjust lower with the Eldorado. It was a nasty mineralization test, and the Eldorado did well.
They are quite close in performance, but since the Vaquero is just a little quieter in typical iron trash, I'd give it the nod for hunting iron infested sites. Overall depth? I'd have to compare them side-by-side again because the last Eldorado I had did quite well, in the ground I was hunting in.
Monte