Don't take what I'm posting here as an insult or a thrashing in any way shape or form, that's not my intention. I don't know how long you've been detecting but your post sounds very familiar to the many I've seen over the years.
Some points I want to make may or may not pertain to you directly but some may benefit from it.
The Quattro is just a user friendly version of the Explorer, plain and simple. The Explorer itself is probably the MOST advanced detector ever produced, sure it has some faults or quirks that some users don't like but all in all (I feel) it has the BEST electronics available on the market.
To many times I've seen people buy a high end detector like the Explorer and expect to fully understand what it's capable of right out of the box. Simply put, until the end user spends enough time for everything to click and understand the detectors language it's not going to be FUN. And, there is NO magic wand/detector that can be bought and waved and the user expect the finds to just start popping out of the ground.
I don't own a Quatrro but I did use one for a solid 2 months, every day, and well after learning the Explorer. I'd have to say it is EXACTLY what it was designed to be, a user friendly Explorer.
Same great depth, and, depending on how it's set-up to hunt it can be just as quick as the Explorer if you're willing to LISTEN to everything (hunting wide open screen).
Sure the EX II is quicker to recover while in disc mode than the Quattro but it's more of a software and extra features issue than anything else, that goes along with the extra price of the EX II.
I know hunting with a wide open screen is noisy but most of the people that are successful with an Explorer or Quattro hunt strictly by sounds anyway. This wide open screen process will REMOVE the constant nulling and then the recovery speeds goes way up ... even on the Quattro. Both machines were designed to hunt slow ... period ! That's how the software is loaded into the detector from the factory, it takes more time to cover ground but the Explorer/Quattro won't miss much for others to find.
I guess it all depends on what the user is willing to put up with for the rewards. Just because a wide open screen is noisy doesn't mean much to me since I've learned the Explorers language. After time, my mind just simply turns off to the junk sounds and when I go over a good target and hear a good one, well it just stops me in my tracks and then I look at the screen if I need to.
Kind of like learning how to drive a straight shift car, once you've done it enough times, you just don't think about it anymore, make sense ?
The Quattro is a good machine, no it doesn't have a back light or some of the other options of the Explorer but it is a powerful detector in the right hands. Either way, if you put in the time to learn the EX II or the Quattro ... you will be rewarded with good finds.
The forums are GREAT for asking questions and getting tips on this and that but when it comes to high end Minelabs, nothing will beat time spent in the field or the thousands of holes dug during the learning curve.
Remember one thing, any high end detector is only as good as the users ability to use it.

For what it's worth, after almost 4 years of using the Explorer, I think I'm about 3/4 of the way thru the learning experience ... it's an amazing detector and every time I THINK I have it figured out it teaches me something new.
Good Hunting
Mike