Ethereum is still the best smart contract platform. It is the biggest smart contract platform to date. Ethereum smart contracts are coded in solidity, a language suitable for smart contracts.
Ethereum has the "code is law" approach to smart contracts. That means, contracts are locked after they are written. They can't be changed. The only way a smart contract could be changed is a hard fork which is very unlikely to happen.
This provides better decentralization and cryptography secures the tokens. But it has its demerits which is, if a bug is found in the code. It can't be fixed and the developers would have to abandon their tokens and fork it on a new smart contract.
I would guess as a smart contract investment the best is probably ethereum. It's used by more people, has a strong community behind it and has many smart contract tutorials about the solidity programming language on youtube and ethereum.org. It's arguably the strongest blockchain platform for the near future.
Of course, the main drawback is ethereum's functionality isn't exclusive. This means competition against the investment. Anything that can be done using ethereum in principle can also be done on the ethereum classic network. Right now ethereum classic smart contracts aren't anywhere as popular but there's no guarantee that will always be true.
As everyone else has said, Etherium hands down. Although I'm still holding on to quite a lot of LEND that I doubt will ever return to the purchase price.
Well byteball did their steemit airdrop not quite long. I will suggest bytesball. Fast and simple to use. It is user friendly.
The good thing is their data is not stored on the blockchain but the DAG Directed Acyclic Graph
I like Ethereum as a smart contract platform the best still. I had high hopes for EOS, but it's not really were I want it to be when it comes to smart contracts yet; they require a lot of expensive RAM, and it's still a lot more complicated than Ethereum. But maybe it will improve to become better than ETH in the future though.