Discuit is the best alternative to Reddit in the market at the very moment, the developers/admins are very open to community feedback and they continue to do a good job in keeping touch with the community. Their API is openly accessible, and many third-party devs have already started working on mobile apps with the Discuit API. DIscuit will also soon go open source in a few weeks, improving trust and transparency.
I've been using this for a few weeks. The sub-communities are very empty, but the UI is good and development seems to be moving at a good pace. I think it has potential if they can figure out the community-building side of things.
I joined Discuit at the 3000 member level. The platform is still in its infancy with regards to features, but the developer is forward thinking and has a sound foundation of a product thus far from which to build.
Regardless of available features, a social media platform is only as good as its community and the site developer and admins have done a good job fostering a healthy growth and community based cohesion to make Discuit a welcoming and engaging place to reside.