DeepSeek released R1, an open-source reasoning model comparable in performance to OpenAI's o1, making it the first open-weight model to surpass state-of-the-art closed ones. This has significant implications for developers and companies like Greptile that rely on AI tools for bug detection in pull requests. Benchmarks suggest R1 outperforms o1 on SWE-bench, a popular benchmark testing models' ability to generate functioning PRs from real-world GitHub Issues. The author tested DeepSeek R1 by reviewing real-world PRs and found it vastly outperformed OpenAI o1, catching bugs and antipatterns that o1 failed to detect. This suggests that open-source models can now match the performance of closed-source counterparts without sacrificing security or performance.