I'm not sure what exactly qualifies as a Android, but Anilaza just in Dragonball Super I would consider more powerful then 17. Go outside and we have DC androids like A.M.A.Z.O and Hourman 1 million (?). So I wouldn't say he is the most powerful in fiction, I'm also positive some exist that I know nothing about.
Peak versions of Amazo can copy/attain infinite power(literally)... So I'd say him.
...Unless Thought-Robot counts. /shrug
"A great tactician creates plans.
A good tactician recognizes the soundness of a plan presented to him.
A fair tactician must see the plan succeed before offering approval.
Those with no tactical ability at all may never understand or accept the plan.
And when a mind is too deficient in understanding, the resulting gap is often filled with resentment."
If Cell had the chance to train while being alive again, pretty sure his potential would outclass 17 getting stronger through training with animals or whatever he did as a ranger, but 17 still a cool guy now regardless.
Thought Robot? Suppose ya got me there. I first saw Amazo in the JL cartoons, but was disappointed when I looked at most of his comic versions in comparison.