How long does the iOS7 update take?

I have a iPhone 4 and am debating wether or not to update to the iOS7 I have heard and read mixed reveiws about it.
So my questions are
•what is your opinion on it
•how long does it take
•should my phone be fully charged beiges or will it charge while its doing it
•what does it change and is it for the better or the worse
Thank you:)

- I wish I haven't updated it. It looks unnatural to me.
- It took me about an hour or so, but it's different for everyone.
- You should fully charge it, but it doesn't really matter if you don't. However, iOS 7 makes my device have a shorter life span and that sucks to the max.
- It changes the way EVERYTHING looks. Just go search a picture of it. I'm not use to how it looks so I don't like it.

Hope this helps:)

My opinion on it is that it is really good and you should really update it!
It's takes about 2 hours or less on my ipad mini it took only 45 minutes! However on my friends' it was less than 4 hours… But with the iPhone 4 it probably would be about an hour.
You can easily just plug in your phone and charge it while it is updating.
Finally, it changes a lot with the security being better, the animations are much cooler looking, and it has many new features that make it a lot simpler. For example, you can change the brightness, volume, music, lock screen etc by just swiping up from the bottom instead of pressing the home button twice. And that is only one of a few cool new features.
That is pretty much it but just saying you should back up your iPhone so if anything ever happens while it is updating and it deletes then you have a backup, but you don't have to it is just optional!

I love it! It's beautiful and fresh.
It took about 1 hour for mine to update.
You should have at least plenty of battery when updating or you can update it while recharging.
Overall (personally) it's better. Just get use to it and learn the new tricks.