Which software is better for Mechanical Design & Drafting CATIA or Solidworks?

both are from the same company, refer to their quotes. CATIA states: Virtual Product. SolidWorks states:3D Design. 

In CATIA, you can not only create a car, but a factory in which it will be produced, the machining processes required, and even you can simulate ergonomics studies as well, like weather the current layout of a plant will be comfortable for workers to work or not. So you can simulate the whole thing within a virtual reality, including, and of course, rendering. SolidWorks: well, it is purely a product to design machines. But, of course, there are other applications, like aerospace, automobile, consumer products, etc. Much user friendly than the former one, in terms of modeling, editing designs, creating mechanisms, etc. I look at the two by this way: Create an aircraft in CATIA, but create the engine in SolidWorks! 

solidworks. as its user interface is far more better and simplified. it is more applicable for big complex designs

According to your Industry and usage the software can be changed. let's  say you are using some normal drafting design say Automotive body you can go for CATIA but some serious mechanical design i prefer to chose the SolidWorks because some serious calculation and some engineering/Mathematical solution solidwork is good. also for testing the both software as this facilities since both software birth from same mother. and 

CATIA mostly uses for shapes design. but SloidWorks for Big Solid,Surface and assembling and testing

but also affect in budget too.