* Small and pocket fit and lightweight (EOS and G12 I have)
* Good image quality (but no DSLR claim!)
* Manual settings (not first have to click through complicated menu)
* Short time from power on to trigger
* Short time between two images
* Not zuuuuuu expensive
I have very difficult me done with my decision between the 255HS and the S110. So really in love I have in any of the two cameras. Since both advantages and disadvantages, I decided only for 255HS, but then I, because I did not have the manual controls, swung around to S110.
* Small: they are both
* Handy: Because I like the 255 by its rounded shape better. The S110 is too square and too edgy. The flash pops up at an unfavorable point of the housing.
Weight: the 255 is lighter (144g), comfortable, the S110 weighs 198g
* Good image quality even in automatic mode: since both work pretty neat. However, I shoot mostly with P or M, in the S110 is also available with Av and Tv. The picture quality is indeed above all depends on the choice of settings and since you can manually simply much much more reach.
* Running quickly: both, however, seems to me the S110 to be faster when it comes to make two images consecutively. The IXUS takes longer to eg load the flash again and then be ready for operation again. Also felt the S110 faster in terms of shutter lag (the time between pressing so triggers and make image). When some 255 snapshots are my unsuccessful because the delay was too long. The S110 works better or faster in the ways.
* Snapshot suitable: with the 255 movements came not clear (children photos). Here lacked the ability to manually intervene and enter the time. Since the S110 offers the possibility, I think they are snapshot-compatible, as long as you know your way a little with photography and the settings. In automatic mode, the S110 is just as able to cope with movements such as the 255HS. Once the light conditions are not optimal, the moving objects from becoming blurred due to long periods automatically selected. Since then the children are missing or sports programs.
* Zoom: The 10x (24-240mm KB) Zoom the 255 is very nice, the S110 has only a 5x (24-120mm KB) Zoom
* Battery life: Is both within the normal range, I think as long as energy guzzlers, such as Wi-Fi is turned off, a spare battery is recommended for both. ADDENDUM: The S110 the battery is not great ... I've always two (!!) replacement batteries. But watch without problems in my Bundle Star * MANGA II camera bag Universal Chic in * Black / White * (Fit Models: See Product Characteristics), so not a real problem.
* Display: The touch screen of the S110 is a fine thing, and works well. The sensitivity is comparable with my iPhone. However, I find the display of the S110 something greenish unlike 255HS.
I would recommend the S110 to those who value it, to intervene in the settings. This makes the 255HS to very limited. I have the opportunities not enough. If you just look for a small lightweight camera to always carry and want to take pictures without a lot Einstellerei, I recommend the 255HS. Incidentally, the S110 looks in shiny-white in combination with the metal really chic ;-)
ADDENDUM: I use the S110 for several months and am now heavily inspired by it. My G12 I sold. I shoot only with my EOS 650D or the S110, where it is currently mainly the S110.