The Challenges You Faced in Substrate?

We have 350 plus validators running the chain and we built an Ethereum Oracle which distributes the rewards to them. The biggest challenge, substrate, the biggest challenge was actually rust and the reliability of a blockchain which we ran. So we'll be migrating our chain to a different ecosystem. Do you know what you're going to migrate to? Yes, we're pretty convinced. We have tested several ecosystems. I probably don't and I just commit to myself now just to be safe but we're pretty sure.