Just from experience I think ( don't quote me ) but vs a melee she would be pushing the lane last hitting regardless , just because its a melee vs ranged lane and she has massive dmg on her auto attk.
I've never lost to a Cait in a solo... Cait's easy.

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Shes good until a gank comes from the jungle.
Good warding, use traps effectively and don't push lane but use time between last hits to harass :p
Edit: not saying she is great, but viable. She has great range which means that she can even push and not extending as far as usual top-laners.