I like NEM, IOTA, and NEO

NEM: It's the most advanced, already POS actually better as it's POI (proof of importance), combination of a public and private block chains, fast, low fee, pragmatic business friendly smart asset, active, building reputation in emerging markets, etc.

IOTA: Uses Tangle not blockchain. This makes it possible for micro transactions quickly with no fees, quantum computer resistant. Tangle is infinitely scalable, as it gets faster and faster with more users. (my thought): Has first mover advantage with Tangle. Tangle needs a lot of users for it to work well, meaning it could be difficult for clone Tangles to compete and take over.

NEO: Possibly going to be huge in China. https://squawker.org/analysis/chinas-cryptocurrency-neo-will-change-the-world-as-we-know-it/

all three still have room to grow, each one has a market cap around 2.5 billion, compared to ETH 32 billion or BTC 70 billion.