Those two cameras are in two different categories.
The Canon S95 is classified as a Point and Shoot camera. (it is near the top of the line)
The Olympus E-PL2 is classified as a mirror-less DSLR (digital single lens reflex) camera.

Both cameras produce excellent photographs.

The E-PL2 has more features including the ability to change lenses.

The S95 does not perform as well as the E-PL2 in low light situations.

Here is a review of the E-PL2 camera:

The last page of the review, has full size sample images that you can download.
Here is a link to that page:

Both cameras will soon be replaced with a new model.
Canon S100 and Olympus E-PL3.