The Teknetics G2 and G2+ are another version of the tried and true 19kHz gold prospecting/relic detector, the Fisher Gold Bug. They are excellent detectors and are very hot on low and medium conductors like iron, gold, aluminum, lead, brass and copper. They are good for coins and jewelry too and can even function in wet salt beach sand to some degree. In my opinion they have a fantastic, simple to set up and use threshold based “All Metal Mode. Depending on the coil used and mineralization level of the soil, you can expect up to 11” or a bit more of depth on coin sized targets along with rock solid numerical target ID past 6”. They are one of the best US nickel detectors I’ve used which also means they will hit similar ID lead, gold nugget and gold jewelry targets really hard. They are extremely sensitive on smaller gold nuggets and micro gold jewelry when using smaller coils. They are lightweight, easy to learn and have lots of different DD coil possibilities that are both OEM and aftermarket.
They are basically the same detector and aside from the faceplate and pistol grip they are also the same detector as the Fisher Gold Bug Pro and the Fisher F19 which have different faceplates and an S rod along with different stock coils. The Teknetics G2+ and the Fisher F 19 have four features added to them that are not on the Teknetics G2 and Gold Bug Pro which are a 10 segment master volume control, 10 segment iron volume control, an up to 20 segment notch discrimination movable window, and an adjustable red tinted backlight. Those added features are activated through the menu/ground grab button and mostly improve the discrimination mode of the detector. They are not available (except for the backlight) in all metal mode. So if you want to hunt mostly in all metal you need good quality headphones with in-line or some other form of volume control.
If you put the same coil on all of these detectors, set them up the same way and test them on the same target you will get the same result. So to directly answer you question, the G2 and the G2+ are the same detector with the G2+ having a slightly different faceplate (a menu/ground grab button and a separate pinpoint button) and the four additional features already mentioned which can help a relic hunter somewhat and are very helpful when hunting coins and jewelry.
Jeff