Yes, I have to agree
Yes, I have to agree, the iOS 4.0 made my iPhone 3G much slower. However, in the eyes of Steve Jobs and Apple, since I purchased my iPhone nearly 2 years ago (08/08/2008), its ancient.
Its Apple's way of saying "Congratulations, your iPhone is now out of contract with AT&T, so upgrade to a new iPhone 4 and renew your commitment with AT&T for 2 more years."
Meanwhile, Sprint is offering G4 when AT&T's 3G network is ho-hum here in Peoria, IL (metro pop 360,000). All the while Sprint is offering G4 -- which includes WiMax. What's WiMax? It means that if you are staying at a hotel that either has no or slow WiFi, or charges $10/day for use you can simply carry a WiMax box in addition to your laptop and Sprint G4 phone and surf the web all you want on your laptop. Yes, laptop teathering ... and good for up to 4 devices which should be more than enough for any family or business travelers. Of course, at this time, in the state of Illinois Sprint G4 is only available in Chicago. However, I believe that AT&T's G3 only became available about a year ago here in Peoria.
Anyhow, my iPhone 3G is SIGNIFICANTLY slower due to the "upgrade" to iOS 4.0. I'm ready for a speed-up and believe that this update was obviously rushed out the door to launch iPhone 4. Apple has a habit of their lowest common denominator being the hardware that shipped in the last 6 months, anything else is ancient and needs to be replaced. Easy to say if you work at Apple, but not otherwise.