[Leica] Highly Intelligent Crop Factor Overview

[Frank Verizon1]

Smaller format sensors can use smaller lenses. Less weight is important to many of us. Leica lenses are small but heavy.
The Fuji kit is small light and effective. A properly selected Nikon kit can do as well. Probably Canon too. 
What you get with small sensors is tighter angle of view. More telephoto, if you will.  Good for the birders and sports guys. 
What you lose is on noise ( given same pixel count the sensor spacing is tighter which equals higher noise).  You also lose big time on wide angle use. If you are a really WA shooter, then small sensors are a pain. You need to get new really WA lenses or change how you shoot. 
If you want MFT,  APS-C, or Minox then go for it. Just know the advantages and challenges for your way to shoot. 

Frank Filippone