Gemini fan here! (Thanks for the intro Chuck) I own the G2V (basically the same as the G4V with 2 channels) The advantages the Slate has are the colored pads its lighter, smaller, and the layout for headphone and other audio jacks are on the side which may not be a plus depending on your set up. The G4V has a full metal enclosure so it is heavier but it feels really solid. although multi colored pads would be nice you don’t really need them. The GV series also has more buttons and controls which add more value especially if you don’t mind a little mapping. It also has xlr outputs which the slate does not.
Long story short the slate seems like a lower level controller focused at the Mixtrack pro level where it seems quite capable. The G4V, on the other hand, is more of a mid-range budget pro controller.
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