Randy,
I don't think you made a BAD decision with the Quattro purchase, that is ... "IF" you give it enough time to actually LEARN the detectors language.
You can't compare the X-Terra (single frequency) detector with a Quattro, Explorer or even a Sovereign for obvious reasons.... ie. (multi-frequency) units and software used in each application.
I've been hunting with Explorers since they were released and owned several Sovereigns along the way. I got the chance to use a Quattro for 2 months after they were released and thought it was worth every penny they sell for. Again, the biggest thing to overcome with a multi-frequency detector is getting familiar with it's language. I agree that the Quattro has a slower response time than the EX II (while is disc mode) but if you make yourself run it in ALL METAL mode and hunt by sounds only, you'll find out that not only does the Quattro have a very good recovery time but you will become a lot more successful in the field.
Many people over the years will get a high end (multi-frequency) Minelab and give up on it because they hear all of those sounds and it just overloads their brian ... but those that learn to SLOW down and LISTEN to what's it telling them will find out quick that the tones rarely lie.
Just look at the quality finds posted on the forums by the users that have took the time to learn their detector ... it's NOT simply luck.
The Quattro is pretty much a simplified Explorer with a few less options and different software but it will hunt every bit as quick in all metal ....
You can bet one thing ... if I spend that kind of money on a detector, I'm going to try my best to learn what it's capable of.
H.H.
Mike