http://www.nikonchat.com/s4000-coolpix/

What to choose between the Coolpix S610, S620, S3000, S4000 Nikon?
I need a fast camera to take good photos and very small. I do not know much about the cameras.
I buy the Nikon Coolpix S550 a few days before a vacation, so I had no time to read the manual. Takes excellent photographs. I tried some of the moving objects at a distance just for fun and they are too light. I recommend this camera. I read several reviews and found many of them helpful. I do not think the noise ISO "is valid for a regular Joe photographer also loads of difficulty of the battery is not valid charge battery charges quickly and easily. This is a great little camera, long battery life between charges and a 4 GB SD (add separately) that has a buttload of pictures. I like and, in fact, fits nicely in my pocket, I have taken it with me the last days of a show – has some photos would not have achieved with a bulkier camera because I would not want to lug a big camera.
Nikon Coolpix S4000 Hands-On Overview from PMA 2010