Ok so despite owning the Reds, I bought these too, couldn't resist.
The fit on the Zero 2 with the tips that come already attached to them in the box (red ones) is absolutely fantastic for me personally. On account of the smaller size of the Zero 2's they feel like a custom iem fit almost for me, flush with my ear and just IN there. The flush fit means be worn with a winter toque without problem.
I upgraded the cable just cuz I always have to do that lol.
In terms of sound, the stock tuning is a lot of fun, when you're out and about or doing chores around the house this is great sound profile imo.
Amir's eq changes chill things out a bit and are nice and clear on the high end.
So for me, stock tips fantastic, cable is passable but might as well upgrade.
As for the Reds, my brain which might be wrong feels there's a bitttttt more detail you can make out? Maybe? But the fit on them isn't as good due to their larger size. I still will use them at my desk and for on the go the Zero 2's are my new go-to.
Great product.
EDIT: Come to think of it, with the tips fitting so well, and these FREAKING IEMS costing about as much as a couple of higher end replacement tips, do I just buy two?? lol