I have tested GPT-6 Astra this week. It is a show horse, not a workhorse. Super fun to use and showy, does crazy good stuff, and design-wise it's the most interesting model I've run. But I don't know if I'd use it for a real day to day engineering/product work. It's not as trustworthy as the Fable class; it feels more like Opus weight with prettier output. But it's really fun for vibe coding and landing pages!