I've been using Cursor pretty extensively in the past few months and I use it to code pretty hard problems sometimes, and a while ago when the options were between claude 3.5 sonnet vs gemini 2.5 pro, there was such a significant difference in quality that claude 3.5 often straight up failed -- the code it wrote woudln't work, even after retrying over and over again, and gemini 2.5 pro often was able to solve it correctly. In a particular project I even had to almost exclusively use gemini 2.5 pro to continue to make any progress despite having to wait out the thinking process every time (gemini was generally slower to begin with, and then the thinking process often took 30-90 seconds).