4/3 and m4/3 was initially developed by Olympus as its preferred format for entering into the digital photography world from the film era. Oly/Zuiko created Digital Lenses made specifically for sensor optimization in a digital system as opposed to film, since they discovered that light hit the sensor at an indirect angle causing noise, digital artifacts, etc. Soon after initial research commenced, a collaboration occurred with Panasonic (who joined for lens manufacture with Leica) to fully develop this format. In the meantime, Canon and Nikon were adapting sensors to their DSLR systems and lenses, so that the legacy lens owners (especially all the Canon and Nikon shooting pros) from the film era wouldn't be abandoned. In many ways, 4/3 has provided innovation, quality, color rendition standards, and much more to the Digital photography world. It's still evolving, as is Full Frame sensor (its only real competition), with refinements and improvements happening every product cycle. Today, I wouldn't hesitate (see my sig!) to commit to a top shelf micro 4/3 system and expect wonderful results (which I get), with far less weight and size.

As others have pointed out 4/3 is obsolete replaced by M4/3.

The best M4/3 cameras and lenses will not technically match the best APS cameras and lenses but they come so close you may not notice the difference in every day shooting.

The real advantage is the IQ for the size, weight and cost. No other interchangeable lens system has a zoom lens equivalent to 200-600mm for under $500. Will it match a Canon or Nikon 600mm...no but at $8-$10K you would expect better performance.

There is nothing close to it for the money.

I like popcorn, hence the coconut oil. Be careful of the saccharine. Even though it came back on the market because researchers changed their minds about the connection between it and bladder cancer. beware. My dad was diabetic since he was 33. He had to take insulin twice a day and the only sweetener available at the time was saccharine. He was a less than moderate user of it and he took very good care of himself. Well, he got bladder cancer and died from that. He only made it to 71. I just love big business.