I get the feeling that he did not like it overall. He gave the S45 a much higher review.
I thought he gave it a pretty good review over all. At the bottom of the comparisons page 2 he said, "The S400 performed very well, delivering the same resolution as its big brother the PowerShot G3. The only difference between the two in resolution performance is nearer to the edges of the frame where the G3 will be sharper. This places the S400 at the top of its class of camera." And at the end, he said "My opinion is if you can afford it stick with the PowerShot S400, you're unlikely to be disappointed." The primary complaint seemed to be the $500 price.
I have very few complaints with my S230, and I was similarly pleased with my S110 before it. I want a very small camera that I can carry with me on various trips that I can pull out and just click the shutter and count on decent pictures out of it. Higher end features like more manual control, and raw mode format are not things that I am interested in at all. I want small size, simplicity and good looking photos. I know the S230 gives me this, and it sounds like the S400 does it as well. When the price falls below $300, I'll have to consider upgrading again.