Only to invest in Ethereum isn't a good choice. For sure it will definitely rise in value but there are also other platforms that run smart contracts very similar to ETH. Antshares, for example, has much in common with Ethereum and scalability is no problem for them.
Also, there's the all-in-one digital asset solution build around Bitshares. EOS builds the Smart Contract part into the Bitshares environment. Combined with their own decentralised trading platform called Openledger opens the Bitshares Wolrd many possibilities. By the way, the creator of BTS & EOS is also the co-founder of the well-known social media tipping platform steemit (Steem).
Last but not least we have IOTA. Last week some news got Leaked out of the BOSCH Intranet. That made one more time very clear that IOTA is working together with big names. BOSCH products are used by almost every car manufacturer worldwide. Because of zero transactions fees and the best scalability in cryptocpace i think IOTA is the one to connect our critical infrastructures with blockchain. IOTA is very flexible and is able to communicate with other Smart Contracts like the ones build on Ethereum or any other.
So in the name of diversification i prefer to invest in Ethereum, Antshares, Bitshares, EOS, IOTA & for sure (we don't have to talk about) Bitcoin & Litecoin. For me, that's the base technologies of future blockchain infrastructures. For sure there is much more great investment opportunities like the niche cryptocurrencies Siacoin.
SECRET TIPP;):NEM (XEM) is very interesting. The founders are very focused on quality and don't give much on advertising. That's the reason why NEM(XEM) is totally undervalued. I can be wrong but i think 3 Million NEM's are needed to run a Masternote. So, Hurry up friends.
PS: Sorry for grammar & spelling. I'm still learning...