9 Life is great if you have Guppy Paw since you can go back up to 3 health everytime. But yeah, you usually try to not die with dead cat. It's something I avoid taking unless I have a ton of Spirit heart or it's my last piece missing
Something I wondered about, I know picking up the Dead Cat drops you to 1 health, but if you have a lot of other types of hearts already, do those get removed as well? Was in the womb with azazel, had like 3 hearts, 4 dark hearts, and 3 soul hearts at the time, kind of "noped" when I got one to spawn out of a gold chest, figuring I was having a good run(did, first time I ever saw the Cathedral, had a bible on me for It Lives, then finished it after never seeing it or that boss before), but I figure one of those achievements is going to be getting the three guppy items in one run, and that was the third I'd seen...