Maui454,
you made a good choice. The Equinox in Gold 1, Gold 2, Park 2 or Field 2 using the 6" coil will hit sub .1 gram gold and will scream on any target over .25 grams. I usually hunt with it in Gold 1 or Gold 2, but you can set up custom Park 2 or Field 2 mode in the user profile in 2 tones and have a really good ferrous tone/non-ferrous tone detector which works. The Equinox 800 has everything you need feature wise even without a true threshold based all metal mode. The Gold modes running in Multi being mostly 20 and 40 kHz and the Nox being a very high gain detector give it plenty of punch especially with the 6" coil. It handles hot rocks and ground noise very well too.
I have used every non-pulse induction gold prospecting detector on the market today and the Equinox (like it is in every other category of detecting that it was designed for) is right up there near the top of the list. The Goldmonster, the Gold Kruzer, the Gold Bug 2, Whites GMT, are all outstanding medium to high frequency gold specific detectors. The only other gold specific medium to high frequency detectors that I really like are the XP ORX and the Whites 24K with the 6.5" round coil. I have had some amazing results with the 24K both in testing and real world detecting with that combo. I know some people don't care for the 24K. I was one of them until I got my hands on the 6.5" coil. The XP ORX is also an excellent gold prospecting detector with the white High frequency coils. They have all found me gold. So there are lots of great non-pulse induction detector options out there.
I do have a TDI SL but I have modded it quite a bit AND I don't use any of White's coils (sorry White's, your stock coils..... yuck!!!!) I use Nugget Finder coils which make the TDI SL running at around 15 volts a fairly respectable, lighter weight PI that I don't have to get totally strapped into or need shoulder surgery after using it. Someday, maybe Minelab or some other manufacturer will make a user friendly Pulse Induction gold prospecting detector for girls and guys over 60 that is comfortable to use...... Gold prospecting is hard enough work as it is.
Jeff