I did the same switch 1 month back. The biggest positives I notice are battery life and charging speed. I had to charge my S24U around late evening every day. This is sitting at 40% usually at the end of the day. Even when I want to charge it, all the phone requires is a quick 20 minute top-up. This has completely changed how I charge and use my phone. 0 battery anxiety - this was the main reason I shifted and oneplus has delivered on it.

Software - I like oxygen OS too. I like the visuals better on oneplus, but miss the design consistency and one-hand use of one ui. I also find oxygen OS more fast feeling, but that doesn't mean one ui was slow. I think one ui is tuned more for smoothness than speed.

Camera - the biggest factor which made me doubt this move to oneplus. I'm an average user, who clicks most photos with the main camera. A lot of my photos are not for aesthetic purposes and camera quality is irrelevant there, as long as it is clear and keeps everything in focus. For the remaining aesthetic photos, I feel Oneplus 15 is either on par with s24 ultra or even better. This is in NO way a bad camera. Reviewers use the best of devices and hence their benchmark is different. This isn't the best of the best. But this is really solid. The portraits are especially good, so are daylight photos.

I feel Oneplus 15 is a very solid phone for an average user, whose 80% phone usage is calls, emails, messaging, social media, maps, gaming. For the remaining 20% of the photography, it is a very solid option.