We ran Cursor against GitHub Copilot on three real Java projects: a Spring Boot microservice (~12K lines), a legacy monolith migration (~60K lines), and a greenfield REST API. Two senior developers alternated tools daily for three weeks.
The results were clear enough that both developers switched to Cursor as their default before the test period ended.
The fundamental difference between Cursor and every other code AI is that Cursor knows your whole codebase. When you ask it to "add error handling consistent with how we handle it elsewhere," it actually goes and finds how you handle it elsewhere.
On the 60K-line legacy migration, we asked Cursor to identify all the places where a deprecated API method was called and write replacement code. It found 23 call sites, got 21 of 23 exactly right on the first pass. This task would have taken a developer a full day manually.
We used Composer to add a new authentication middleware that needed touching seven files across three packages. The first pass was 85% correct — one file missed a null check, one had the wrong import path. A second prompt fixed both.