Once again it comes down to areas that you intend to detect, if PI detectors have cleaned out the area, it is likely they have taken anything at depth that the Gold Bug or Gold bug Pro could possibly detect. Hence leaving smaller gold for detectors like the Gold bug 2 to clean up on. A lot of areas that Steve regularly detects in will be completely different to the conditions we face here, with highly mineralised ground that will test the depth capabilities of a mid frequency detector like the Pro. High mineralisation = lower sensitivity settings = reduced effective depth.
On the other hand, if you wish to also detect for jewellery and coins, the Goldbug Pro would probably be the more sensible option, with better depth than the GB2 and useful features like the ground grab button vs manual balancing all the time, and the ability to balance all the way to salt, which will be useful at the beach.
The Goldbug Pro is really aimed at the new generation of detectorist, gaining all the features you would expect to find on a versatile multiuse detector, vs the Goldbug 2 which is a more specialised machine that may not appeal to the masses, hence it doesn't really compete against the GBPro. The GBPro is most probably made to compete against the likes of the x-terra 705, Tesoro Lobo, Garrett ATGold and Whites MXT E-Series, whereas the GB2 is by its lonesome against the Whites GMT.
