Here is my two cents about iOS5 sofar. I have been using this since friday and already I have found a few things to be both annoying and awesome.
First of all I love it.. All the changes is great. but first the bad things:
It feels like my phone is really slow since loading the pre-release version of iOS5. I find that certain applications will take longer to do certain stuff than it used to on iOS4. Then again it might be because this is the pre-release so I will upgrade on Wednesday and see how it goes. Another thing I notice is that certain apps keeps on crashing after a while running. Not sure if this is related to a iOS5 incompatibilty will have to wait and see aswell.
I also notice that my battery seems to drain alot faster than on iOS4. In the week I will be on my phone alot ( talking, texting, notes , etc ) and if fully charged in the morning it will be at 20% around 15h00 in the afternoon.
Today was sunday and I wasnt on the phone alot at all and by 14h00 the battery died. Once again this is just observations and I will check this again once the official update is out.
On the plus side: I really enjoy the integration with twitter, its super easy getting connected to Twitter and sharing photo’s etc. Newsstand isnt operating yet as the store button is greyed out. iCloud rocks sofar! I love it.. got my stuff everywhere all the time and now being able to sync my documents and spreadsheets right from Pages / Numbers ( on ipad ) and be able to view them on the net is really a awesome luxury.
I love the read later feature, reminders, new notifications and the ability to sync to itunes without having to plug my phone into my pc via a cable.
I also noticed that on iOS5 you can install multiple apps simultaneously. ( as far as I know on iOS4 there was a queue where one would finish then the next starts. )
All and All I love this.. I am sure I left out alot of featues but I am still exploring. I cant wait for the official release and for iPhone 4S.