safari was regularly locking up when browsing fb, other apps still worked fine, but once safari had locked it wouldn’t work on other sites too
You shoul be using the Facebook app, not safari for FB, I have never had safari crash on my 4s or iPad, you must have a suspect phone.
I know what you mean about the size of the screen, ive had a desire for 2 years, so it’s taken a while to get used to tescreen but I like it now, the build quality is way above Samsung, the iPod function is the best of any smartphone, the camera is superb, the iCloud is brilliant especially if you have other iOS devices.
Stick with it I would say.