I've been using ios 7 GM on my iPhone 5 for several days now (didn't install any of the betas). I didn't do a "clean install".
So far there's only three issues that are bothering me:
1) If you have the triple-click "Accessibility Shortcut" enabled (like I do for inverting colors), then home button responsiveness is significantly reduced. This isn't a problem at all with ios 6. For now I just have the triple-click feature disabled because I don't invert colors often enough to endure the extra lag every time I press the home button. I shouldn't have to make that sacrifice though.
2) Settings app crashes occasionally.
3) Slower animations and slower opening apps. My wife's 4s on ios 6 opens stock apps faster than mine now.
For me it's just overall not as snappy as ios 6. However, we're talking about milliseconds here, so it's not intolerable. I wouldn't give up the extra features to go back to ios 6 just to get a slightly more snappy general navigation experience.
Control center is great. Notification center is also better, and it's nice to be able to get to them both without having to unlock the phone. Swiping anywhere to unlock instead of specifically sliding the arrow at the bottom like in ios 6 is a handy feature as well. You kind of have to train yourself not to aim for the bottom all the time, but once you do that you realize that it is indeed easier to unlock the phone now.
The photos app is much improved in my opinion, allowing you to see your pictures organized by dates. However, besides "years" the rest of the preset time periods that photos are grouped into (collections/moments) are not static. The app just decides how to break up these periods. One "collection" for instance can cover 3 weeks while another one is just 2 weeks. Then under that one "moment" might be 4 days while another is only 2 days. It would be nice to disable this "smart sort" feature and instead let you determine a specific time period that applies to collections and moments. Or just add one new setting that ditches the "collections" and "moments" sorting option in favor of years > months > weeks > days.
The most desired feature I feel that is missing from the photos app is the ability to see specific properties of a single photo. I would like to be able to long press a single photo on the cameral roll, and be presented with an option to view its properties so that I can see the timestamp of when the photo was taken and its filesize, for instance. Right now the only thing you get when you long press a single photo is a "Copy" option. So...the photos app is a significant step in the right direction, but not quite where it needs to be IMO.
Camera seems fine. Battery life seems fine. Email is better (finally a "mark all" option!). I'm still trying to decide whether I like the calendar better or not.
As for the general look and feel....I'm almost indifferent about it. I guess I'd have to say there's too much white going on. I'd really like for ios to have a "night mode" option or something like that. My preference for a dark background with light text is one of the reasons I had the triple-click for invert colors function enabled before. In low light situations I have occasionally inverted colors or when I'm reading a long text article.
I could go on a little more, but I don't wanna get too long winded.
