Tbh, it comes down to S-Pen support, Sound Assistant and Pop-Up window. I could mention DeX, Good Lock and I recently explored HeX Installer... which has been dope (can't believe I didn't jump on it when @Bkdodger brought it to my attention).Slightly related but unrelated question: for those of you who like One UI and daily drive a Samsung phone, why do YOU like it? I'm asking because I've tried time and time again to like and appreciate it (I've owned S22, Flip 4, Fold 4) but I feel I'm either scratching the surface or don't need a lot of the features that One UI brings to the table. I flip flop between various Android phones and the iPhone quite regularly, I have found that I prefer the Pixel UI and I really like Material You and the fun animations / smoothness it brings. However, I can't last with the recent Pixels because with my dry skin the fingerprint scanner drives me up the wall. I want to like Samsung more than I end up doing.
But those 3 key features will keep me on Galaxy phone until something irresistible comes along.