If I had to choose one, it'd be the Democratic Party, but that's over the "lesser of evils" conclusion that I came to.
I find the Republican Party, especially at this point in time to be inept at both creating policy, and just even creating a consensus as a party for what policies should exist. I find their reactionary nature to only be applaudable for their adherence to their beliefs, but that isn't enough in my eyes when their attempts at making policy do not seem to consider the impact of their proposals if it were to be law. For that reason I consider them to be naïve in the context of policymaking. Something I really appreciate about the Republican Party and conservatives in this group is that, by contrast to the other parties and especially as a larger party, they are more multi-generational—as long as you fit with our creed, you're accepted here.
I find the Democratic Party to be somewhat unified, but I find that they are too focused on fundraising and getting control of power strictly on the terms of the establishment, to the point of rejecting a candidate who had a very good chance of winning the 2016 General Election. Their policies are also shortsighted, but in my mind, tend to consider the impact a little more than the Republicans do. Their tendencies toward neoliberal economics and global tactics is nothing short of divisive. Something I really appreciate about the Democratic Party is that they tend to exude compassion to every American, by contrast to the Republican Party which makes a point of drawing lines between deserving and undeserving of liberty and opportunity.
While my knowledge and experience about the major third parties, I find them extremely lacking in both sense and solidarity. The principal reason why they are not major parties, in my eyes, is not that they are simply poor policy-makers, but that they are poor politicians. I honestly haven't seen anyone yet who runs within these parties who has a truly comprehensive and contextual knowledge of the state of our Union. They have a grasp on their own agenda, but not very much beyond. Something I appreciate about the third parties is that they are non-conformist and original. Some of the proposals of the third parties (although few in number), I believe will benefit America, as they take a new shape of governance, and demand fairness within the political system, whereas the major parties seem to muddle this critical area of our politics.
As with any political system, this is an imperfect one, and we as people with party affiliations need to focus first on making sure it works rather than making sure we win.