How does this perform with *very* large state trees and modifying smaller points? It seems to me that the performance for comparing changes, or tracking changes would either mean a lot more memory usage, or be significantly slower with very large state trees.
No IE10-11 support should probably be spelled out on the homepage (per your observable dependency)... as many will be severely surprised when they find that out.
I submitted a benchmark here: https://github.com/krausest/js-framework-benchmark/pull/185. It will hopefully be merged soon. It performs better than Redux and MobX and slightly worse then optimized pure React there. I will send PRs to more benchmarks in the next week.