I am thinking about purchasing one of these and they both have their merits. When I used to have an an Olympus camera one of my most used lenses was the 12-40. The image quality was excellent as was stabilization on the E-M1. I sold that and moved on Sony systems. I am keeping the Sony FF system but missed the light weight and lens choices in m4/3 for travel and more casual shooting. I recently purchased a GX85 with the 12-32 and like it. However the slow lens doesn't work well in some circumstances. With the GX85 body would you go for the 12-35 2.8 that works with the dual IS on the GX85 or for the slightly longer range and (maybe) better image quality of the 12-40 2.8? Would not having the dual IS be a deal breaker for a stills shooter?