There are only a few platforms being developed right now. By platforms I mean blockchains which have an application layer sitting on top that can be used for DApps, smart contracts etc
There is ETH, well established, this year will be a good one. Hopefully a bunch if current issues will get sorted out. Many of you know the services, tools and ICO's happening on it.
NEO, earlier 'AntShares' and also the ChineseETH. The promotor of NEO is close to Chiese regulators and govenment. I think NEO is a safe bet in the perspective. There is some tools and ICO's already starting to happen on the NEO chain. In any case holding NEO's in your wallets also gets you some return in the form of GAS.
Waves, another blockchain development platform, not really popular as of yet; though it does have a functioning platform. I think there has been one ICO on it; dont know for sure; someone can pitch-in
Then we have the platforms under development.
Cardano (ADA) also known as Japanese ETH

Although they currently are not functional; dont have a testnet; they are really shooting high as a platform. They are developing a very sophisticated blockchain that is supposed to be generation 3. They seem to have a unique development process that is rigourous with third party auditing of the code (Some microsoft alpha team) . The code itself is written in a functional language (Haskell) that makes writing code less bug-prone. Also the promotor was a cofounder at ETH
EOS: also a platform, they just have a testnet out. Though it seems promising I dont have too many details.
My bet is on Cardano and NEO, over to you folks...