If, in the mania of the 2000s, things could head towards $6.7tn, I don't believe that this bubble will be smaller in the age of loose monetary policy.
Money is essentially free today. A few weeks ago, Saudi Arabia paid $450m for a painting. If that isn't a sign of how money has lost its value, I don't know what is.
Would I bet everything I own on crypto? No, of course not. Can you still get a 10x return on money you invest today? I wouldn't be surprised. Even knowing there will be a major correction at some point, it's probably a mistake not to own at least some.
They're both Turing-complete blockchains which can run decentralized apps/smart contracts, and of course be used for transactions directly.
Ethereum (ETH):
Created in 2015, currently successfully running. Right now ETH uses a proof of work consensus algorithm with plans to move to a proof of stake algorithm over time. Its smart contracts can be coded in two purpose-built languages, and work is being done on cross-compilers to facilitate writing in more. ETH can currently handle ~20 tx/sec, but the community is very active in working toward vast improvements in this regard via very technical solutions (sharding, plasma), but they're not quite there yet. Ethereum is truly decentralized and runs tens of thousands of validating nodes.
EOS:
Planned creation date is in June 2018. Its smart contracts will use WASM (allowing the use of many general purpose computer languages), support parallel computation, and have some sort of ability to change deployed contracts to allow for debugging and updates. It will handle 100,000+ tx/sec out of the box, and transactions will have 0 fees. Instead of fees, percentage of holdings determines allowable transaction bandwidth (If you have 1% of EOS, you get 1% of EOS transaction throughput).
However, instead of tens of thousands of validating nodes, EOS will have 21, with all coin holders having the ability to vote for who these validators are. EOS will trust the consensus of these validators for transaction security. This is how EOS achieves such high transaction volume and zero fees. IMO, this is the main weakness of EOS.
In the dotcom bubble, people were buying shares at prices such that justifying those prices would require companies to make more money than any company had made before. But people, including experts, said this time it's different because the internet will change everything, and those companies really will make more money than any company has before. Even though no actual hard data justified that optimism.