Well, if you really want to know what Garrett has been up to, a patent search or two will give you hint! I can't tell with certainty from the patent holder's name, because I don't know the employees are at Garrett. In any case, the name Garrett doesn't show up. However, there is a late patent (last 18 months), that describes a pulse induction detector with resonance discrimination. If indeed that is what the new detector does, it is yet another step forward.
I think most detectorists have a basic idea of how their detector works, even though the technology behind them is fairly complex, especially ones which table discrimination (comparing the received frequency and phase shift against a know pattern). In reality, it isn't rocket science although some might think so. The real hard part of designing a metal detector which can meet today's demands from us diggers, is a juxtaposition between processor power, battery technology, and affordability. If we had unlimited funds, ground-based radar systems using interferometry would be readily available, and inexpensive—they aren't!
I'm also of the opinion that some technology stinks! The double D coil is one of them. It is true that they work better in mineralized soil conditions, and perhaps (urban legend?) detect deeper. But they still offer poor pinpointing. I regularly use a Garrett GTI-2500, and most of the time I don't need to use my pinpointer, especially on coins. I'll stick my neck out, but if you live in an area with low mineralization, it's fairly hard to beat a BFO detector. Yes, they don't discriminate, but sometimes you don't want too!
If they ask me what I wanted, it would be a switchover to Lithium battery powered units, color touch screens (think weather proof), and much lighter weight (carbon fiber construction?).
