I've found it slower than Claude but:

- significantly less obsequious (very few "you're absolutely right" that Claude vomits out on every interaction)

- less likely to forget and ignore context and AGENTS.md instructions

- fewer random changes claiming "now everything is fixed" in the first 30-50% of context

- better understanding of usage rules (see link below), one-shotting quite a few things Claude misses

Language + framework: Elixir, Phoenix LiveView, Ash, Oban, Reactor

SLoC: 22k lines

AGENTS.md: some simple instructions, pointing to two MCPs (Tidewave and Stripe), requirement to compile before moving onto next file, usage rules https://hexdocs.pm/usage_rules/readme.html