On the witness side, things are pretty good. I personally run three 32 GB RAM servers for my witness, and I have a 32 GB RAM public seed node.
Steemit recently wrote a post regarding the scalability concerns. It sounds like things are under control.
https://steemit.com/steemitdev/@steemitdev/steem-blockchain-update-august-2017
Thanks for that link! Imma read it.