When you look closely, it’s not such a gentle upgrade, after all

The new iPhone hits the streets today and, as usual, there have been queues of eager Apple fans outside Apple Stores for days. With over 1 million pre-orders in the first 24 hours, it’s expected to sell well.

But this seems like the slightest of improvements over last year’s model. Apple’s handset now has a 1GHz dual-core central processor but others are faster. The iPhone display is still 3.5ins - small next to many smartphones.

So why is the iPhone 4S, which even lacks a shiny new design (it looks nearly identical to last year’s iPhone 4) set to conquer? I’ve been using it for a week to find out.

Well, beauty is more than skin deep, we know. Apple seems to have taken this to heart, giving the phone a big internal makeover. The new, peppy processor may be outgunned by rivals, but this is fast enough: apps launch instantly and web pages build fast.

Then there’s Apple’s secret weapon. It’s called Siri, a voice-activated personal assistant, which nobody else has. Sure, there are apps like Vlingo and Dragon Dictation which offer impressive voice recognition for dictating messages, but Siri goes further. You talk in colloquial English, for a start. Ask if it’s going to be chilly in London tomorrow (though, to be fair, that’s an easy one) and it’ll say “No, seven degrees doesn’t seem all that cold”. Follow up with “How about Monday?” and Siri tells you Monday’s weather.

It’s integrated into the phone so you can ask it to remind you to pick up your dry cleaning when you leave work. When the phone’s GPS spots you’re moving, it pings you a message.

It’s not perfect – the software is still in beta stage – and struggles in noisy environments, but Siri at its best is dazzling.

The other reason the iPhone 4S is likely to thrive is because it fixes the biggest problem of the iPhone 4: signal quality. The retooled antenna system is superb.

There’s an updated OS which makes it the most advanced, accessible interface available plus a hardware design that remains as beautiful as it was last year. That display isn’t huge but it has the highest density of pixels of any phone (and it shows). Overall, when you look closely, it’s not such a gentle upgrade, after all.