Large APS-C (23.6 x 15.7 mm) sensor
Large sensor in Leica TL ensures a good low light image quality compared to smaller sensor, and it also provide shallow depth of field and a nice blurry background when needed.
Medium size Body
With relatively smaller body compared to DSLRs and better ergonomics compared to Compacts,Leica TLis a good compromise between size and functionality.
Carrying this weight all day may not be very comfortable for you.