i've been coding with Grok 4.5 Fast for the entire day, and this model has officially replaced Opus 5.
it doesn't make any sense, Grok 4.5 is:
1. cheaper
2. faster
3. smarter (in some areas)
i've given the same exact task to both Opus 5 and Grok 4.5 Fast, and Grok finished it in 33 minutes, while Opus 5 was still "working on it" for 58 minutes...
then when I asked Opus 5 what is was doing, it said,
"you're right, I got carried away. let me continue on the task I was assigned"
this model is literally acting like a human employee...