Can anyone confirm if maps is usable on an iPhone 4? I had the first beta on for about 20 minutes before I had to take it off as most of the apps were either extremely sluggish or nothing loaded at all (i.e. mail and maps). And yes, I'm a developer and have had every beta of every version since the first one, so I know to expect beta software to be, well, beta - but I felt that the first release was truly the worst one I've come across. What was your experience like?