Just adding a bit to this comment:
They are great layers until their molt after a year at which point they just stop for a few months. Then, even after they resume, it's never quite as productive.
Add to that the fact they don't live long(3 years is good), it's definitely not something to look at with a ROI eye.
My experience with GCs is that they'll live as long as can be expected of any chicken and their drop-off in productivity still puts them amongst the very best.
But I'm about due for some layer replenishment. What do you think is a better choice?
There's like 3 things basically the same (ISA brown, Golden Comet, Cinnamon Queen), all red sex links, and they are the best all rounder you can ask for. Best layers, not broody, docile. I've had just about everything, but this year just raising random mixes I got as eggs to let the kid incubate.
So I think you already found the best. I didn't mean to refute anything you wrote, just adding some context for passer-bys.