I agree with this...I don't know what they did to the iPhone 3G but it runs like a dog now. They really need a software update to bring it back to the speed it used to run at when it first came out. I think it's definitely slower and less stable now.
Do you have iOS 4.1? If you are on 4.0, it is tragically slow, but since my finances were so tight, I was forced to suck it up and deal with it. iOS 4.1 improved things to move the phone along and preform basic duties without crashing. But, for a phone, it is frustrating to wait 15 seconds when you are in a rush for your phone contacts list to load, so you can make a call. Also, the iPod feature, does it really need to take 30 frigging seconds to load?
I am an Apple computer user for the last 4+ years, and been generally happy by the experience. I must admit, their hardware is usually expensive and much slower than their competitors. But, the OS experience that their computer systems offer is top notch. As for iOS, I am NOT impressed, and been keeping a very close eye on WebOS 2.0. WebOS 2.0 is what the iPhone OS should be like.