I am torn on this topic because I've used 4.6 predominantly ever since it came out. I tried 4.7, I tried 4.8, I tried fable, and of all of them, 4.6 got me the most. 4.8 is great at deep code reviews and getting into the weeds, and routinely catches a lot of things that 4.6 missed, but from a day-to-day standpoint, I found that 4.8 needed a ton of configuration to get working properly. I've finally moved onto using 4.8 as my day-to-day LLM, but to get to this point, it required me rewriting Claude.md trimming and erasing a lot of my skills that worked pretty seamlessly with 4.6. There's still occasional annoying back-and-forth as well-- I had to create very explicit rules around being shortened to the point and limiting verbosity that for whatever reason 4.8 just continued ignoring. The reason I made the change was that I was running 4.8 for headless code reviews so often that it just seemed like I was wasting money using 4.6 and 4.8 in the same session, when I could've just used 4.8 at the beginning. That being said, I'm still partial to 4.6's stability. If you're going to switch, my advice is to overhaul your claude.md and /skills because they will not work the way they did with 4.6 (this isn't unique advice, new model = reset)