App optimization
Apps on iOS felt much compatible, optimized in a way such that social media apps (particularly Instagram, snapchat)are able to retain the quality of images and videos especially when it is posted as story (not post). For instance, I wasn't able to upload a smooth video story on Instagram, android's ig always compressed my video to a point where videos are very choppy as compared to ios ig. Of course, i don't blame android for this since there are so many android devices, app developers may not optimize their app so that it is compatible on every android devices.       

Gestures
Gestures on iOS is simpler IMO, much easier to control everything just by using gestures, like swipe right from the edge to go back (it works on almost every app, like fb, photos, WhatsApp) or swipe down after seeing the photos on fb/album. But android relies very much on back button, so it feels like there are not much gestures on android. Apps on iOS merge very much with the gestures, using gestures on iOS apps is smoother, like I am able to see the transition and animation, I couldn’t experience this on android before. I do appreciate if android is able to implement gestures like iOS on android, it makes controlling and handling the phone much easier. Thus, it feels better control on iOS at least on my side.

Fluidity and speed
IP11 may not be the fastest device, but what I can tell is it indeed is one of the smoothest devices compared to my earlier device (OnePlus 6), but speed is what i experienced on OP6. Fluidity on iOS might be due to its animation or other factors? I'm not entirely sure about this but at least that's what I experienced and loved it.

Battery
Standby battery is much better on iOS, I'm able to squeeze more SOT as compared to android, might be due to google play service on android which is sucking my battery juice (this is the problem I have not been able to solve since early android stages).

IOS or Android
Will I ever stay on iOS? Yes, I would, and now I do understand when people talk about it's hard to change to other devices once you've tasted iOS due to apple ecosystem (few of my friends did tell me that when I asked about their opinion of switching to iOS). It's only a week of using iOS, and I'm already loving it and used to it, feels very much in control.

Will I ever switch back to Android? Yes, I would, if android apps (social media apps) are being optimized and keep up as iOS devices. But android does have the option to sideload apk (something iOS couldn't do), that's what I do miss on Android.