I've a N900 and an iPhone 3Gs. My wife has an iPhone 3G.

The N900 detects wifi networks both iPhone can't see, and can connect to networks the iPhones can see but can't connect to.

Still missing LOTS of things from my 3Gs (I've given myself two months before selling one or the other), but when I leave my house, the phone I keep in my pocket is the N900