What will I lose when I update my iPhone 4 to iOS 7?

I currently have a 32GB iPhone 4, and I've never updated it before. I still have the original software that I've had ever since I bought it at the Verizon store. I'm planning on updating to iOS 7, but I'm just worried that I'll lose my important text messages, notes, and other stuff like that. What are the pros/cons of updating to iOS 7? Will I lose any of my important data?

As long as you have backed up your data to iCloud, nothing should be lost. However, I strongly suggest not updating on an iPhone 4. Models 4S, 5, 5C and 5S are the only suitable devices for iOS7 and your phone would be very slow on iOS 7.

You won't lose anything but IOS 7 sucks. I did it this morning with my iphone 4 and I wish I didn't.

But as far as losing anything, No. I kept all my texts, notes, music, emails, etc. It only updates the software.

Just an update on what the person below said, the only reason I don't like it is because of the way the icons look and also the way they keep things in the background different than before. As for speed, my iphone4 is either exactly the same or maybe even a little faster

So take advice from someone who actually has your same phone (me). The person below me doesn't know for sure, they are just speculating. I actually have your exact phone. The speed and keeping your files etc is fine. I just don't like the new icons and other things like that.

You won't lose any of your important data if you back up with iCloud/ iTunes. Like what they say, iPhone 4 sucks with a iOS 7.It hangs often and is slower than the iOS before. Don't update unless you really love the design, etc.

Nothing.

You gain through iOS updates.

No idea why you presumedly stuck with iOS 4 all this time.