Proponents of Ethereum ignore the fact that Ethereum fails to address any of the most significant problems in Bitcoin. Bitcoin's major advantage is decentralization, and it's about the only thing that Bitcoin does better than anything else. Bitcoin is an extremely expensive way to build a financial system, and there's no reason to go through the trouble unless you are utilizing the decentralization.
Bitcoin's major problems are scale, miner centralization, and developer centralization. Ethereum is worse than Bitcoin in all three respects. Transactions on Ethereum are heavier, develoepment is very heavily controlled by the Ethereum foundation and by Consensys, and the block algorithm in Ethereum more strongly favors larger miners as compared to Bitcoin (which already favors bigger miners).
Further, the Ethereum develoepment team is under qualified. There have been several ametuer mistakes, including allowing negative balance, leaking private keys, and putting consensus at risk by advocating that different users should be running different consensus codebases. Most of the highly capable developers in the cryptocurrency ecosystem avoid Ethereum because it's not been constructed well, nor does it's design suggest strong resistance to adversarial environments.
Bitcoin did go through similar growing pains. Bitcoin did have many ametuer mistakes when getting started. But those have all been fixed, and there is a positively enormous amount of competent mindshare powering Bitcoin, and the thoroughness of decentralization in Bitcoin is unmatched by any altcoin, including Ethereum.
Ethereum has offered a lot of cool tricks with its turing complete scripting language, but is standing on a house of cards. It scales less well than Bitcoin, it's design more heavily promotes centralization, it's development is more ametuer, and the potential applications offered by its fancy scripting language are not actually that much stronger than what you can do with Bitcoin. The showcase applications such as Augur and Slockit suffer from weak cryptographic fundamentals and under-qualified developers even worse than Ethereum does.
Bitcoin's major problems are scale, miner centralization, and developer centralization. Ethereum is worse than Bitcoin in all three respects. Transactions on Ethereum are heavier, develoepment is very heavily controlled by the Ethereum foundation and by Consensys, and the block algorithm in Ethereum more strongly favors larger miners as compared to Bitcoin (which already favors bigger miners).
Further, the Ethereum develoepment team is under qualified. There have been several ametuer mistakes, including allowing negative balance, leaking private keys, and putting consensus at risk by advocating that different users should be running different consensus codebases. Most of the highly capable developers in the cryptocurrency ecosystem avoid Ethereum because it's not been constructed well, nor does it's design suggest strong resistance to adversarial environments.
Bitcoin did go through similar growing pains. Bitcoin did have many ametuer mistakes when getting started. But those have all been fixed, and there is a positively enormous amount of competent mindshare powering Bitcoin, and the thoroughness of decentralization in Bitcoin is unmatched by any altcoin, including Ethereum.
Ethereum has offered a lot of cool tricks with its turing complete scripting language, but is standing on a house of cards. It scales less well than Bitcoin, it's design more heavily promotes centralization, it's development is more ametuer, and the potential applications offered by its fancy scripting language are not actually that much stronger than what you can do with Bitcoin. The showcase applications such as Augur and Slockit suffer from weak cryptographic fundamentals and under-qualified developers even worse than Ethereum does.