• Micro Four Thirds cameras are small and unobtrusive (even less obtrusive than a rangefinder camera),
• MFT cameras are light and easy to carry,
• the larger depth of field due to the smaller sensor enables you to shoot at f/4 with the same d-o-f as with f/8 on full-frame, yet twice as fast shutter speeds.

Cologne, Germany | Olympus E-P1 + Lumix 20/1.7 @ f/4, 1/200 sec, ISO 200

For more thoughts and pictures see my thread in the dpreview Micro Four Thirds Talk discussion forum.