For me (on Linux) the font is much prettier and much easier to read in Firefox. Firefox also seems to render it lighter than Chromium-based browsers.
replyEdit: I looks so different that I really thought it was falling back to a different font, but the Google Fonts page produces the same effect.
https://fonts.google.com/specimen/Cormorant+Garamond
On my Android (Chromium based browser) it renders very thin and dark as well. On Firefox on Android, it renders the same, but much lighter.
How odd! I did some research into why people have been finding it looks odd and it appears to be tied to Mac doing something called font dilation to slightly fatten up thin fonts when displayed as light text on dark backgrounds, whereas Linux/Windows don't tend to have such a feature enabled by default. Shows how long it's been since I made any attempt at good typography, I've never heard of this before!
replyI've bumped the brightness of the text on Linux/Windows to hopefully make it a bit easier to read/overpower the anti-aliasing thinning it out. I'll have to go fish out an old ThinkPad to test it properly as I ditched most of my machines outside of my Mac when I quit programming full time (I don't really like any OS but Mac is still the easiest for photo/video I find).