Lets get this ETH critiques straight to the point.
Scalability sucks; the blockchain design fundamentally relies on bottlenecks where individual nodes must process every single transaction in the entire network.
PoW is extremely expensive, and furthermore is fundamentally vulnerable to 51% spawn camping attacks with no effective strategy for recovering from one. Selfish mining is profitable starting at 25-33% hashpower, and 51% censorship attacks are definitely profitable.
Privacy sucks
It's hard for regular users to hold large amounts of funds without running substantial risks of theft or loss due to theft or loss of their private keys.
Economics do not encourage good “storage hygiene”; insufficient incentives for clearing storage and insufficient cost for filling it, especially for long periods of time.
Bunch of various marginal technical inefficiencies.
It's hard for regular users to know that contracts they are interacting with do what they say they do, and do not have accidental or malicious bugs.
Reference: Internet