At first glance the Galaxy Z Fold 4 isn't particularly different to the outgoing Z Fold 3. But then this isn't really an 'upgraders' phone in my view. Since using the newer Fold for a fortnight I've found the marginally different aspect ratios make both screens – whether the exterior in folded...
Slightly better screen aspect ratio screens than predecessor, It's a lot like a phone and a tablet rolled into one, New Taskbar functionality for enhanced use-cases, Camera improvements over its predecessor
Wait until you see the price, Under-display camera is still too visible, S Pen stylus isn't integrated – and sold separately, Screen creases and reflections unavoidable with folding tech