Dash has the most long term stability of all mineable coins. That's why I recommend it. If it's buying, then I'd pick ETH or NEO. Mining contracts take 2 years, so stability is more important. If you need a quick buck, Bitcoin Cash is pretty great. It's more of a short term thing though. If you don't like Dash much, go for ETH. I'd say stay out of BTC and LTC because they are practically what Internet Explorer was some years ago. They came first and they'll die first.

Good luck with mining!