I love the people that say its a 4s with a bigger screen (just because they cant afford an iphone 5)
It has a different processor, better front camera, better video recording, better speaker, better battery, lighter, better colours and the more important thing - the new lightening 8 pin connector which means the phone now has a digital connection instead of analogue.
All devices will eventually move to this new 8 pin connection (saying this based on the cost to apple incurred for changed to 8pin from 30 pin)
Better processor - It's a phone not a gaming rig or something I want to render Toy Story 3 on. The 4S is rapid at everything I want a phone to do.
Front Camera - Who ever uses this anyway, plus the one on the 4S is perfectly adequate for functionality like Skype/Facetime.
Better Video Recording - Again the 1080p HD recording of the 4/4S is fantastic already. In fact the camera on the 4S is pretty damn good for a phone. I can't imagine it being much better without venturing into dedicated compact camera territory. In fact I've just been in Thailand and some of the pictures my gf took on her iPhone 4 were as sharp/clear as those I took on my Nikon J1 which is a dedicated mirror-less compact SLR-substitute.
Better Speaker - A phone speaker is always going to sound tinny and shoddy.
Better Battery - Now you've touched on a relevant point, it may be better but it's not anything to get excited about. If it was some awesome battery that lasted days on end then yes, a major point.
Better Screen - Yes it's bigger and more vibrant but it's nothing compared to the jump from the 3GS to the Retina display on the 4 which was groundbreaking. The screen on the 4S is still brilliant.
Lightning - I appreciate it is needed for the future but being digital instead of analogue has little implication for the everyday user right now.
There's just nothing ground breaking about it. It's just slightly 'better' in some departments. I have no problem with people who want to upgrade to have 'the latest and greatest' but I'm sick of hearing people go on about how great it is. Guess what, it ain't.
I'll ignore the chip about being able to afford it.