I got the S110 as a replacement for the S95 after the lens servo basically died. I'd used the S95 primarily as a second camera to my T3i. The S110 was quite an improvement and because of its portability, actually supplanted my T3i as my go-to camera for travel. The most notable features were the touchscreen, which made focusing much easier, particularly for macro shots; the ability to save in RAW; and the improvements in the click wheel around the lens. The most obvious drawbacks have been the low pixel count (at least compared to the T3i and even my cellphone) and relatively minimal amount of optical zoom, although both of these are trade-offs for the small size.
Overall, the S110 a very useful camera, but with the maturation of the Sony mirrorless range, I can see this getting squeezed between my next camera (and first non-Canon digital) and my phone.