Hi All,
It seems it is the fact that memory isn't cleared completely when we quit an app. I sent feedback to Apple on this subject. There is an App in the store called Memory Info. This will clear unused memory. I have experienced sluggish apps, quit that app, run Memory info then restarted the app and it is much faster. This works consistently. I think a daily reboot and this app will make things workable for most people. No we shouldn't have to do this but let's realize that the iPhone is cutting edge tech. The other phones on the market do not have the flexibility and fluidity that the iPhone does have. I believe the only way a platform can truly be tested is in actual use by the public. Beta can only do so much. There will be an update that will address issues. If we give feedback..
http://www.apple.com/feedback/iphone.html
Then they will have a record of the issues people have.
The iPhone isn't for everyone yet. It is pretty advanced. It takes some commitment to understanding it's quirks. So far for me it has been a very reliable phone. If I need to make a call it works. If I need some information I can find it. There are lags. Some are unacceptable. There never seem to be any with the phone app though. That is a place a cell phone has to be flawless. This one is in my opinion.
Greg