Well, we’re back to the prevailing model from years gone by – namely, if you bought your iPhone last year, there is not that much to tempt you; if your iPhone is two years old, run don’t walk.
The changes are mostly incremental – once again, the iPad processor makes its way into the iPhone (and once again, it is suspected, with even more RAM). Once again, the megapixel and HD capacity of the cameras gets a bump to the next general tier. Once again, battery life is slightly improved, and once again, there’s a single new big-ticket feature that’s hardware-dependent (true A-GPS in the 3G, video capture in the 3GS, Retina Display/FaceTime in the 4, and now Siri in the 4S).
If you’re still packing a 3GS, you should put in your order now. If you have an iPhone 4…well, there are two things to wait for. One: how will iOS 5 perform on the iPhone 4? Given that it’s all we’ve had to test on to this point, one has to assume it’s broadly feasible (you’d want to be mad to run it on a 3GS; I know Apple is trying to preserve long-term viability but I suspect you’ll be sorry if you try to bump a two year old iPhone to the new hotness) but it’d be nice to see for sure, especially if Siri is so processor-intensive that it needs a 4S. And two: is the whole thing really capable of both CDMA and GSM? Could you finally get a Verizon iPhone and take it abroad without a fight? How will this work? Will this work?
So far, it looks like I’ll be sticking with what I’ve got. I reserve the right to change my mind, though, if the Verizon performance is so good (and the prospect of going to the UK/Ireland so high) that I can justify making the switch…