I have used Proteus, Eagle, Diptrace, Designspark, Target 3001, Kicad, etc in the past to design some simple boards. But none of the programs really sat right with me. There always was some aspect which caused a problem, mainly with having to create symbols and footprints. For me, as a hobbyist, the cost of a full blown version was just not justifiable and the licenses are simply too restrictive. But I made do with the limitations.
Then recently I stumbled upon the Youtube channel for Contextual Electronics and the multipart tutorial Getting To Blinky 4.0 for using Kicad 3.x. Goodness gracious, the improvements made to Kicad are just phenomenal. What an easy program to use now. And it is freeware.
My designs are still not all that complex, just microcontroller stuff, so I don't know how one would fare with it in a professional setting, I would suspect quite favourably though.