I suppose despite of all this hype around Bitcoin there are many alts that can compete with it in future. Ethereum has already proved that it is №1 to be next to Bitcoin.
I agree with you about Ethereum.
Among other altcoin, Ethereum seems to be the best choice to pair with bitcoin (meaning second position after bitcoin).
Currently, in addition to having a wide market for trading, Ethereum has smart-contract that are vital to their development, especially to attracted investor interest.