Rand Paul is the best candidate by far in my opinion. Unfortunately I doubt he will be the Republican nominee. Hilary and Bernie are beyond scary options. A socialist and the least trustworthy politician imaginable.
If the Republicans were willing to back Paul, I'd definitely consider voting for him. I've contributed a few hundred dollars to Rand (and Ron's) campaigns over the years.
Unfortunately Libertarians get far less respect in the Republican primary that whatever the hell Trump is.
I still have issues with Paul, mainly that his ideology sometimes takes a backseat when he needs to pander.but I respect a lot of his work in the senate.
But a guy like Ron or Rand Paul isn't ever going to make it in the Republican Party. They've made that abundantly clear.
I'd rather back an electable candidate that is at least pro civil liberties and against fiscal responsibility. Than the rest of the field which is anti civil liberties, and anti fiscal responsibility.