The main advantages are its weight and its very small size, which can fit easily into the bag of my GH1 (along with a 20mm and 14-140), and especially its thread to put a polarizing filter or protector indispensable quality in tourist circuit (I prefer drizzle, sea spray, sand or dust ... or fingerprints ... stick to a filter rather than my goals).
Quality side, the sharpness is very good at photo center from 10mm (equiv. 20mm), and overall good anywhere from 11mm. I personally preferentially positioned at 11mm, even to expand 9mm if necessary because the sharpness is still a notch below 9mm (but it is still very often useful to have a view at 90 ° 9mm). Maximum 18mm does not allow to zoom in on an architectural detail, but still allows to take standard pictures without changing targets, which is appreciable. Note that the deformation (in the direction pad) is well under control, and I did not notice any vignetting despite the use of filters (in this regard, my circular polarizing behaves relatively well, certainly better than I feared: I have met with difficulties of consistency rarely in 15 days).
The main drawback is the lack of automatic correction, including chromatic aberrations: from this point of view, the 7-14 has a distinct advantage because it saves you the tedious job of photo retouching by picture (this being a 9mm distorts perspective and editing is any appreciable vertical to put in place). For clarification, the aberrations are not so slobbering nor very visible as with a converter, but when used to the sharpness of a 14-140 with automatic corrections of the case, it necessarily becomes very demanding.
Another disadvantage (which may seem minor to most) is the lack of support that goal by DxO: hope that this will happen soon, to correct these small aberrations in batch.
In conclusion, I could ask the dive 7-14 with automatic corrections in the housing, but the M.Zuiko 9-18 is a choice I do not regret for my use (mainly pictures of sights during my travels) where the size and especially the ability to mount a filter is essential for me.
I recommend 100% (4/5 note is for the price, my wife making me still regularly noticed that my goals are worth the price of 2 compact cameras like a good TZ8).
