The market is changing at such a rate that the true answer to this question doesn't truly warrant a fixed answer but one that acknowledges a changing space.
Given that we're deep in the infrastructure-building phase of this crypto revolution - my strategy has been to invest in the platforms that are going to enable future growth, Ethereum, Neo, Lisk, Stratis, Waves and similar .
Ark is creating "smart-bridge" technology to facilitate the interoperability and transfer of assets between the many different chains, and I think this technology is very much needed also.
I see Internet 3.0 consisting of a network of interconnected blockchains. Of course, I could be massively mistaken so I invite you to do your own research :)