Just yesterday I ran a comparison of $/message through my harness[0] comparing Deepseek models to Luna, and to my surprise Luna won. I suspect its partially due to Deepseek's long thinking times, and also maybe due to OpenRouter variance in cache pricing etc.

Model and observed window | Messages | Retrieved actual $/message

DeepSeek v4-flash — all observed snapshots, 20 Jul–15 Sep | 4,610 | $0.0241

DeepSeek v4.1-flash — 11–27 Sep, before the 28 Sep billing change | 1,079 | $0.0576

DeepSeek v4.1-flash — 28 Sep, partial new billing window | 69 | $0.0365

GPT-6 Luna — 23–28 Sep, partial final day | 88 | $0.0329

I've subbed to Codex because I suspect at my usage rates the Codex Plus plan gives me more Luna messages than I'm using, and I've not really observed and better or worse intelligence performance. Interested to see how my $/message comes out after a month of usage on the Codex plan.

Something nice I've realised about my harness is that I can run different agents on different models so I can collect pricing data for a bunch in parallel.

[0]: pi-msg, run pi agents over xmpp https://github.com/zachpmanson/pi-msg