One problem I find with ETH is how much the community relies on Vitalik and Vlad. Also an argument against investing in Ethereum might be that its better to have your money somewhere else temporarily, and then move it back to Ethereum. I personally invested in CS and XRM. And also make a better profit with young projects as stellar or credits. There really arent a lot of issues with the project itself. Scaling is said to be the biggest issue, but it is currently handling far more transactions per day than any other network. There are a lot of updates coming, hopefully in 2018, that fix this issue. Overall, Im extremely excited for Ethereum and everyone apart of the community.