The SD43 is thicker and larger in diameter, it doesn't sit nicely as a sub would but if you have a big wrist like mine (7") it'll be fine. It's also heavier and can get uncomfortable if worn loosely unlike the sub. The diver extention is also another feature which you probably will not use.
In terms of the overall looks both come close as the SD43 corrects the issues in the V1, sharp bezel teeth and incorrect cyclops mag.
Both uses 2824 which is wrong for the sub as it doesnt move the same as a 3135 but as for the SD43 its the same as a 3235.
If you like the looks of the SD43 just go for it, you will not regret it, it's an excellent rep ootb.
I do not own a ARF, but having owned a Noob sub before I'd still prefer a sub for its size.
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