The strongest argument for voting for Trump is Hillary Clinton.
The reverse is also true: the strongest argument against Donald Trump is Hillary Clinton.
...and the strongest argument for a third party is Hillary Clinton + Donald Trump.
Sorry got the reverse backwards. Should have been reverse is also true: the strongest for voting for Hillary Clinton is Donald Trump.
Point is they are both horrible. I see them as both being so equally bad that while typing my comment I didn't remember which one you thought was worse.