I've been using it for more than 2 years, and I can't think of ever going back to a stock OS. I had to send my phone for a screen repair, in the meantime I picked up my old Samsung, and the sheer amount of apps I didn't want, notifications and dark patterns to tricking me into handing over my data made me anxious. I couldn't finish setting the phone up and drove to my parent's home to pick up their old, remotely nerfed by Google, Pixel 4a so I could install GrapheneOS into it and use it while I waited for my repaired Pixel 8.
Same. Not only has using it been no trouble, but having a barebones core app selection, a few picks from F-Droid, and using the browser for the rest makes my phone feel refreshingly under my control. It lasts for 3-4 days of low usage to boot, when nothing is phoning home constantly.
~6 months here. In my case, it became almost a full daily driver ( putting corporate spyware on it would kinda defeat the purpose ). It is by no means perfect, but I can recommend it ( and I could not do the same with other phones that should have been better on paper -- linux phones like pinephone or purism ).