I have not "used" blender, per se, just checked/tested to see that it *would* work. It is pretty much like any other 3D software ... in that it requires literally a whole new dimension of thought. How good of an artist are you? How good of a draftsman? If you can draw standard 2d projections of a 3D object, then you should be capable. That said, Blender looked to be more capable than I had skills to do. So, IM(NotSo)HO, it seemed decently straight-forward, but with plenty of upside potential. As a certified (AARP member) geeser, I can relate to feeling the challenge, but engineers have always had to learn new tools, new software, new approaches, so this would be just another chapter and verse. AutoCAD (and really, ANY other 3d software) is about the same level of capability and challenge, as learning Verilog, "C", FPGA design, Chip design, etc. It is mostly a matter of putting in the effort to learn.
Blender's big advantage, is that one can import the main 3D formats, so just about everything "out there" that is available, can be *yours*. With the total investment cost being "merely" time and energy, it beats everything else available. I strongly believe that using free software, when available, is a benefit. The community of users and developers tends to be a LOT more helpful, even considering other types of professional level --- versus --- free software I have used in the past.
As for the actual machine to 3D print, it seems nothing magical past the heater element. Everything else amounts to a well-controlled 3D CNC, of which there are many examples and designs. Remove the heater element, mount a spiral saw to this platform, and 3D machining (to a degree) can be accomplished. Additionally, a double-sided PCB could be "milled" for the routing, holes could be drilled, solder paste added, (should one push the platform), all with little modification to anything but the "head" assembly. I could see buying the heater element, but the rest should be a DIY design capable project.
IIRC, there are some 3D printer designs supported by a hobbiest community, where existing owners/users will print the parts needed to build another unit (short of the heater element, and motors).
Nothing but money ... (stands between me and great wealth)!
Yes, blender is, for lack of a better term, a competitor to 3ds max, maya, softimage and the like. These are all effects packages and used for movies/gaming. While this can be nice (it is where I learned and what I'm comfortable with), it is lacking in precision for drafting.
What you probably want for 3d printing is a drafting package for precision positioning and alignment of assets... like gear teath.
Sometimes you want to model something organic or fun though and that can be incredibly difficult in CAD. Both tools are nice to have.