iOS 5 is Slow?

I currently have an iPhone 4 and an iPad 1 and I have still haven't upgraded to the new iOS 5 system that Apple released a few days ago. Is iOS 5 slow?
A friend downloaded the update and installed it in his iPhone 3GS and he told me that iOS 5 runs very slow and that he reverted to the previous version.
Apple optimized iOS 5 to the new devices, the new phone and the new iPad, but what about the previous version? Is it going to slow them down? Because in that case, I'm not interested on installing it.
Have you tried the new operating system? Did you find it slow?

I installed it in my iPod 4G and I can tell you that iOS 5 is not slow at all, it works as fast as the previous version.
Maybe your friend has problems with iOS 5 because he owns a device that was released 2 years ago and it doesn't have the best hardware.
I understand that it runs slow on a 3GS but so far in my iPhone 4 works like a charm.
Many things have changed in iOS 5 and I really like the new features. The camera has been improved a lot and there are new official applications. I recommend it if you have a device that is not so old.

Slowed my iPhone 4 down a lot. Delays in typing. Opening and closing apps. Another flakey under-tested update from Apple. My iPad is the same by the way. My wife's iPhone 4S works great. Hmmmm. Good luck!

It is slow on older hardware. I can definitely say its slower on older hardware. I upgraded a 1st Gen iPad and a iPod Touch 4G and its made these devices almost unusable with crashing apps and Safari. Not to mention very slow opening of Apps (those that work) and the battery life is much worse! My advice is anything older then one generation back is stay with IOS 4.