I only know this because I've owned both at one point. The Flip 4 being the backup to my Fold 4. I don't understand the allure of the Flip 4 at all. I think it is a nonsensical device, at least for my use case. Why anyone would want to constantly have to flip their phone open to complete even the most basic tasks is beyond me. I grew up in the era of flip phones and while they had their moment in the sun, that sun set long ago. I traded it in for a Pixel 7 as my new backup phone. The Fold 4 on the other hand, is outstanding. I'll never go back to a traditional slab phone again. I will be buying the Pixel Fold on day one, no doubt about it.