The only reason to note vote for either Trump or Clinton is if you believe they are the on the same level of shitness. People are really forced now to make that decision because in the end one of them will be president. If you think Trump is worse, even just by a little bit, then casting your vote for Clinton doesn't mean you support her, you're just helping to keep him out of the oval office. Casting your ballot for Johnson does nothing but take one vote away from the other 2 candidates.
I would say go for it and vote Johnson, but in reality it's probably going to bleed Clinton votes, so you might as well just vote for Trump.