I have an ipad and an iPhone 5 but chose to test the look and feel on the ipad first. Here are my thoughts in general so far...
Look & Feel
The whole device looks clean, uncluttered yet very bright. I cant help but feel there is depth missing to the icons. It somewhat reminds me of another (unmentioned) operating system. I love and prefer the notification center. I love how its is opaque and you can see the blur of the wallpaper. The calendar that shows up on this drop down menu is perfect for my needs.Its cleaner and more simplistic in design. The control Panel is also a good addition, however and there may be a way but i wish to be able to take of the music part as this is not something I need at hand.
The wallpaper and background. As previously mentioned by others is my biggest gripe is the resizing of the background image. I have some wonderful images and when it zooms in when setting the image it really ruins the whole image. I have tried to resize mages etc but still it only zooms in. Here is hoping this is just a bug that may be fixed in a later update. The icons being opaque and showing colours from the background is also good, something i messed about with for a while to get it just right.
Folders
I love the infinite mound of icons i can group together in 1 folder. Gone are the days of Games 1 and games 2 folders. The simplicity as mentioned above is something that follows through in the design with the folders.
Settings
This is something that hasn't changed too much, i did however have to go thru a lot of them and double check they were set to how i wanted them. I noticed some new ones and had to insure they changed in order to consume battery power.
Photo/camera
I was disappointed that I couldn't find filters within the camera app, this is on my iphone yet not on the camera within ipad. Maybe I'm missing something and i am yet to discover this. Anyone noticed its a lot more clearer on the front facing camera?
Safari
On the iphone it puts tabs like this
I would have liked to have seen this on the ipad also. Just a quirky addition that i like.
Battery
Does it eat battery? or do i just play on it too much. So here is the thing, we get a new iOS and we all try everything out and yes naturally the battery falls quicker.. is it because the iOS is draining or because we are perhaps testing every new feature? Battery power for me went down quick on first day, today despite having Bluetooth on to be typing via a keyboard on this post is not going down so quick. Time will tell once i get back to normal every day usage.
Speed
Increase speed on everything, It might be because i have saved a lot of memory and usage by not installing every app pre update. but it all seems smoother, faster and more sleek whilst navigating and using. However, there is a delay on the keyboard in some case. This is not just on my ipad, i have noticed on my iPhone too. When swapping from letter to numbers the delay can cause me to press a wrong key. There are seconds in it but still quite buggy.
Posts getting a bit long now but overall I like the update. so much so I did update on my iPhone also. Im sure anything i don't like will grow on me, which is good because there is no going back anyways. Any bugs will probably be squished in an update soon anyways. We can hope at least!