The highlight of the RX100 VI over the RX100 VA is its unprecedented macro capability. The zoom on the 24-200 mm f/2.8-4.5 zoom lens cannot be beaten by other compact underwater setups. Details captured with this lens are remarkable. When combined with a wet macro lens (diopter), the realm of super macro photography is attainable. The tiniest details of the smallest subjects can be captured with this set up (once you get a little practice in of course).
Which GoPro accessories to get?
Before you start digging into the reviews, a few notes on choosing a cam that's right for you. You'll definitely want to consider frame rate, expressed as frames per second (fps). Some action cameras offer up to 240fps recording, while others only go to 30fps. For standard playback, 30fps is perfectly fine. It's when you want to slow footage down in editing to create dramatic scenes that frame rate matters. Footage captured at 240fps can be slowed down and played back smoothly at one-quarter speed. You may also want to go for a cinematic look, in which case you'll want one that has a 24fps capture option, the same speed used by most Hollywood productions.