Necro thread revival alert. When deciding what CAD software to learn on it's important to decide what you want it to do, just like any other tool. Not a lot of point to using true 3D software if all you'll EVER use it for is flat plate DXF's for the water jet or plasma.
However, if you entertain ANY notions of doing more than flat plate work then I'd suggest skipping 2D and going straight to 3D software. I took AutoCad classes in college until I was introduced to 3D software (Pro-E 200i) and pretty much abandoned AutoCad like a faithless lover. You can still do 2D exports from 3D software but have the added advantage of 3D capability.
Won't rate one program over another as it all depends upon solid vs. surface modeling, the complexity, and size of assemblies you intend to create. Catia is top drawer, so is NX (used to be Unigraphics) but both programs are so very capable that they feel a bit clumsy to work with for fairly simple models. Pro-e/Wildfire/Creo has better surfacing modules but has some drawbacks I find annoying. Rhino is also purported to have good surfacing tools but I've not used it. Coming from a Pro-E background I was disappointed with the lack of improvements for the designer/engineer. Most improvements seemed to be for the other departments (accounting, purchasing, etc.) and the modules/tools I used remained largely unchanged. SolidWorks (Solid-Quirks) I find to be no slower, buggier, or a bigger piece of **** than the other programs in that price range. Same for Inventor. All the programs in this price range have slight advantages/disadvantages over the competition but not enough to make a huge difference in solid modeling, assemblies, or drawings. If you're asking it to work with NURBS from a 3D scan of a part you're using the wrong software. Tessellation is not a strong point either, once again you're using the wrong tool to do a job. Solid modeling is what most of you will need it to do, surfacing is what generates non-ujniform geometry like a computer mouse. You can still do this in solid modeling but it's largely the long way around the task.
My background is 25 years as a toolmaker in the shop and 15 years in mechanical design engineering. I know what's needed in the shop and much of what basic engineering/design needs CAD for. I've worked daily with Pro-E, Wildfire, Creo, SolidWorks, Inventor, and occasional work with Catia and NX. I purchased SW in 2014 for home use because most mid-to-large manufacturing companies used it and Catia/NX were just too expensive. I don't find SW to be all that limiting even for assemblies that have 300 components. The other mentioned programs should be just as capable. If you're designing plastic injection molds then you likely already know what programs to consider and what not to.
Try any of the free or inexpensive CAD programs and see if it does what you want it to do. Several shop owners find that this works fine for what they do. If you do find that your business would benefit from a good CAD program then bite the bullet, pick a program, and start climbing the learning curve. It's not that difficult and won't take months to have the fundamentals. Think of solid modeling like a lump of clay you pull/push/cut to get the shapes/features you want. Your learning should be on tasks you need it to do so you can begin getting some real world use out of it. Plenty of videos and people to ask specific questions about and most of the programs even have tutorials already loaded into them. If a shop donk like me could learn it then I feel just about anybody can if they apply themselves.
Hope this helped someone.