If you are doing a lot of (non-organic) modeling for 3D printing, I'd highly suggest you look into learning Fusion360. It is free, and fairly easy to use once you get the hang of sketches. It completely changed the way I model functional parts now.

After using it for less than a year, I got a gig doing CAD design and prototyping of an electric moped (using 3D printing and CNC machining).