Most people that do Ultrawoman-esque stuff seem to go for a more human, fleshy appearance but with machine parts tossed on.
Personally though? I'd like to see more android protagonists like the ones from NieR: Automata.
A2 is a good example of a middle-ground between the two choices you're giving me.
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In the game she lacks maintenance, which is the cause of her more robotic appearance. Initially though, she would have been much less discernable from a normal human.
If you wanted to sell a character like her very well, you could make her appear very natural when undamaged but transition her into more severe states of disrepair as she takes more and more damage. (Or utilize game over CGs to show that she is in-fact mechanical)