Now that it has been confirmed that the F19 has an all metal mode like the Gold Bug Pro I will probably trade my GBP for the F19. I do not expect the F19 to go any deeper in all metal mode than my Gold Bug Pro. That would be a bonus for me if true but I do not expect it. For my purposes it just needs to be as good as the Gold Bug Pro in all metal mode since that is my primary hunt mode. That way it can replace my Gold Bug Pro and not give up anything, yet gain some features that I personally might find useful.
Basically the F19 appears to be a Gold Bug Pro that comes stock with the 5" x 10" elliptical DD and a few additional features for a few extra bucks. The extra features add value more for relic or coin detecting than for nugget detecting. If the extra features have no value to a person the Gold Bug Pro can still be had for less and will find gold nuggets just as well.
The F19 is "Just Another Mid-Frequency Detector". No big deal, nothing to get excited about. People waiting for "The Next Big Thing" can go on waiting.
My take is that there appears to be no penalty in my having the F19 instead of a Gold Bug Pro and possibly some benefits, so why not? But of course we will not know for sure until we lay hands on them.