I'm honestly really impressed with GPT-4.1 mini. It is my default from messing around by their API because it is unbelievably inexpensive and genuinely capable at most of the things I throw at it.

I'll switch to o4-mini when I'm writing code, but otherwise 4.1-mini usually does a great job.

Fun example from earlier today:

  llm -f https://raw.githubusercontent.com/BenjaminAster/CSS-Minecraft/refs/heads/main/main.css \     -s 'explain all the tricks used by this CSS' 

That's piping the CSS from that incredible CSS Minecraft demo - https://news.ycombinator.com/item?id=44100148 - into GPT-4.1 mini and asking it for an explanation.

The code is clearly written but entirely uncommented: https://github.com/BenjaminAster/CSS-Minecraft/blob/main/mai...

GPT-4.1 mini's explanation is genuinely excellent: https://gist.github.com/simonw/cafd612b3982e3ad463788dd50287... - it correctly identifies "This CSS uses modern CSS features at an expert level to create a 3D interactive voxel-style UI while minimizing or eliminating JavaScript" and explains a bunch of tricks I hadn't figured out.

And it used 3,813 input tokens and 1,291 output tokens - https://www.llm-prices.com/#it=3813&ot=1291&ic=0.4&oc=1.6 - that's 0.3591 cents (around a third of a cent).