Price to performance wise, the SF dumps on the iPhone(s) from a great height. However, I don't think this will be the mobile event of any time period because:
a) the iPhone as much as it is a functional device, is foremost an object of desire for the masses. The SF is an object of desire for the more technically inclined - those who realise the potential of the device.
b) the iPhone is available to every major network, the SF just to Orange.
c) branding, much like a) people want the iPhone because it's a "must have device". A no-brand ZTE/Orange phone will never have this cult status overnight.
I don't miss my 3G, the flexibility of the Android platform is a breath of fresh air after the almost oppressive iOS days. Not to mention having hardware again that I've gone without - camcorder being one! £50 PAYG handsets held that over the 3G, why should you upgrade to a 3GS/4 to get that out of the box?
Even with the freedoms Android return, and the opened armed acceptance of many as this being a great device it's not going to be enough on it's own to defeat Apple's grip. There are too many who covert the iPhone blindly, it's going to take a PR offensive of biblical proportions from Google/HTC to be a surpassing mobile event. Soon though, I reckon it is coming...