I have an S400 and have been very happy with the results. Two things may be happening here:

1. Bump the saturation up. I think the S400 calls it "vivid colors." I use an editing program so I keep things at a lower level in-camera.

2. I am betting that the dfference in clarity is due toin-camera sharpening. Canon is very conservative with sharpening. Sharpening can be added but, once there, can not be removed. Canon leaves things somewhat soft and lets you apply the best amount for each image in imaging software.

You can bump up the in-camera sharpening by setting a higher value in the menus. Be aware that most beginners set the sharpening too high at first and, as taste develops, start turning it down. Experment, after all, shooting is free!

Other than noise (IMHO, Canon is probably the cleanest overall), there isn't really all that much difference with image quality between P&S brands. Before spending more money, go through the manual for the S400 and set the parameters the way you like them.