Herb... that's alright... you just keep using those photos because they make a fine illustration of what the GMT can do over small gold.
Reno... either of these units will hit on tiny gold as Herb has indicated. The Goldbug2 will hit the tiny stuff a bit cleaner but may not go quite as deep as the GMT on larger nuggets as ground mineralization increases.
Both are very capable units, despite that there are differences in how they operate. I prefer the GMT's ground balance choices... there are places where autotracking is useful although I normally prefer manual ground balance. The GRAB feature is quick, easy and accurate... and saves fiddling with the manual option if you find manual ground-balancing a chore.
Both units offer a feature to identify or eliminate signals from unwanted shallow targets in the iron range, but do it differently. I like the GMT's visual readouts, full ground balance range, and the variable SAT feature.
On the other hand, I'm fine with the GB2's manual ground balance, don't really trust any target ID or discrimination except over very shallow iron, and the GB2 is a lightweight unit that can be hip-mounted if you prefer it even lighter. It offers three ground mineral selections to be used according to the ground mineral conditions encountered for optimal performance.
Six of this and a half-dozen of the other... you made a good choice.
Jim.