If you are going for gold and want to look in streams:
Garrett AT Gold (available now @~$640) Max Freq = 18 khz (single frequency)
Minelab Equinox 600 or 800 ($649 and $899) - release imminent Max Freq = 40 khz, Simultaneous Multifrequency from 5 to 40 khz
Makro Gold Kruzer ($649) - release imminent Max Freq = 61 khz (Single Frequency)
Makro Multi Kruzer ($749) - release imminent Max Freq = 19 khz (Individual Multi Frequency at 5, 10 and 19 khz)
All of the above are fully dunkable up to 10 feet (the Kruzers to 15 feet). There are no other gold machines that are dunkable in this price range. First Texas (Bounty Hunter, Fisher, Teknetics) does not make a waterproof machine in this price range. Whites does make a submersible machine in this price range (MX Sport) but it is not a true "gold" machine as explained below.
The maximum frequency is important because it gives you and indication of how well the machine will react to tiny gold. Generally, the higher the frequency, the more sensitive it is to tiny gold. The drawback is that high frequency machines are not as sensitive to high conductive targets such as silver (Gold is a mid-conductor).
So if you want to focus on gold, go for the higher frequency machines Like the Gold Kruzer.
If you want better all around performance go for the machines that have a range of operating frequencies like the Equinox or the Multi-Kruzer. These two machines also excel at salt water hunting because they are very stable, but the Equinox is probably better suited to salt beach water hunting because unlike the Kruzer, it pumps out all 5 frequencies simultaneously (similar to the Whites you were looking at - it pumps out 3 frequencies simultaneously, but the Equinox is not nearly as complicated to learn. Also, you can't dunk the Whites. Whites also offers the MX Sport which is similar to the above but its low low frequency of operation (13.8 khz) does not classify it as a true gold machine).
The AT Gold is the proven machine that has years of experience behind it, but it is a little heavier than the other machines and the technology is a little older. It tends to do the best at cutting a compromise between higher frequency operation to improve gold sensitivity, while operating at a frequency low enough that it is still very sensitive to high conductive targets like silver. A very good example of doing the best you can to cover the bases within the constraints of a single operating frequency machine. Good fresh water machine but not as good as the Minelab and Makros under salt beach conditions due to the single frequency ops and lack of a robust salt beach ground balancing circuit.
The latter four machines (2 Minelabs and 2 Makros) come with wireless headset capability built in.
Even though the latter four have not yet been released there are plenty of videos and confirmed objective testing results to determine that it may be worth your while to wait until they are released in the coming weeks to see how they pan out. It's not like you are going to be jumping into any streams at this time of year anyway. But you certainly won't regret the AT Gold's proven track record unless you experience buyer's remorse after the Minelabs and Makros hit the street.
And, yes, I recommend you buy from one of the Tnet dealer/sponsors and ask them LOTS of questions.
HTH
PS Gold stream prospecting takes a lot of patience and a viable source (not that regular metal detecting doesn't). But if you find that finding gold in streams is not all that and you still want to jump into this awesome hobby for the other hunting opportunities (coin shooting and relics), then that brings machines like the AT Max and MX Sport into the mix. It would be hard to pick between the AT Max and AT Gold at this point. But the AT Max does have some new tech bells and whistles since it was just released in the last few months including built-in wireless headphones and some improvements in the user interface vs. the AT Gold. I think the AT Max and Gold eclipse the MX Sport overall, but the Equinox and Kruzer series detectors may turn out to be serious contenders to unseat the AT series detectors in terms of value and capability. That's my opinion, anyway. But I must emphasize, the AT series is here and now and the others have yet to prove themselves. Regardless, I held off on the AT Max after the Minelab Equinox announcement. The Kruzer announcement was just this week. Specs look promising, but that is all Makro has to offer at the moment. Specs and some short videos of test units. Good luck. And I say again, ask LOTS of questions and try before you buy, if you can. See if you can borrow a friend's detector, regardless of model, just to see what detecting is all about.
