Greetings Kevin. Welcome to the Forum,
Your tool or toy question is an interesting and somewhat challenging one.
Obviously, this is not a tool you take out of the box plug in and just use. It’s not like a jigsaw or sander. No CNC really is. But in this case building the machine is a project in itself. How much “tweeking, tinkering, and putzing” is required will be determined by the choices made while building it and the care with which it is assembled.
For best results your 3d printer will probably require some “tweeking” to produce accurately scaled parts that are “square” in 3 dimensions. The build involves mechanical, electrical, and electronic aspects, all of which offer potential challenges.
Ryan offers kits which include all the required hardware, wiring, and pre-programmed electronics. This is by far the path of least resistance, and definitely the best road to take for someone just looking for a tool to use.
Are you at all familiar with CAD/CAM software? A CNC does nothing by itself, of course, it requires instructions. The CAD/CAM aspect offers a steep learning curve itself.
Speaking strictly to the capabilities of the machine, the Gallery is indeed a good place to start appreciating its abilities, as is the Things You’ve Made category here in the Forum. Here are some of my own projects. I’ll probably be adding something to that list later today. My output is probably not up to the standard of a good avid woodworker, but that’s due to my own shortcomings, not the machines.
While there those making money with their MPCNC, it is not a production machine, and you shouldn’t expect production level output. To be hones, If you’re strictly serious about not “tweeking” the machine, something like a shapeoko might be a better option, but I think the MPCNC is capable of making anything the shapeoko can.