I've been playing with iOS5 for a while and I've come to two conclusions on it. First it's a great update on the iPad. Second its a bit of a let down update on the iPhone.
iOS 5 on the iPad is actually a nice step forward. There are lots of headline features but the three I've found myself using regularly are the notifications on the lock screen, newsstand and the multi-touch gestures. Notifications are actually very useful and I've now find that I have my iPad in a stand beside my monitor and I can see when an email, twitter of Facebook message pops in. Newsstand I assumed would be a gimmick and perhaps it will be but I currently have two newspapers installed for free (the Guardian trial and metro) and I do find myself reading them. I feel the novelty could wear off and I'll go back to just reading the websites. Finally the killer update for me is the multi-touch gestures. Swiping up with 4 fingers to access multitasking, swiping across to switch apps and pinching to close apps have become my usual way of navigating apps.
On the other hand (no pun intended) the multi-touch gestures don't work on the iPhone 4, where I actually need them because my home button is acting up a little so I'd like an alternative to pressing it, especially the double tap to open multitasking. I can understand that the screen is a little small and fiddly for 4 finger gestures but Apple could at least have given us the option. To not have it there is a let when compared to the iPad. The notification system is the one update on the iPhone I regularly use and like.
Other features like wifi sync, and reminders may become party of my day to day use but haven't yet. The photo editing tool is simply too late to the game since I'm already using Photoshop Express and Snapseed. Airplay mirroring to the Apple TV might prove useful some time but it's not something I have a use for at the moment. My wife and I might use iMessage but she's rather sensibly banned me from updating her 3GS at least for now. She doesn't want any of the other new features and doesn't want anything to change so she's happy to stay a version behind until everyone else tests the OS.
All in all iOS 5 isn't a bad upgrade. It's adds some useful features, especially for the iPad but most importantly it's free so it is pointless to complain about anything. Like the iPhone 4S it seems like an incremental update but then again iOS works and works well so we'd all probably complain more if Apple changed it.