I second Alibre, I am using the pro version. I bought it in 2012, and I can't remember if I've paid for upgrades to keep it current since then.

I used it to design an injection mold and I am still using it for 3d printing projects. It's a capable program and on-par with SolidWorks or Inventor for basic modeling.

I haven't tried OnShape yet, but if I didn't have Alibre I'd probably look into that or another web-based program for new hobby projects. I like the idea of perpetual licenses but it's only perpetual for as long as it runs on your operating system.