Hostile to newcomers? I think you posted your question 3 days ago, which is a relatively short time to get a detailed response to a large number of non-trivial questions that span a wide range of topics.
I assume that you’re familiar with the basic differences between additive and subtractive manufacturing? I ask because of the comparison you make to the Ultimaker 2+, which is a 3D Printer, or “plastic spitter” as you call it. There are some fundamental differences in the type of construction that each can be used for which should probably guide your purchase decision. A major one is that a 3D printed object can be built in one piece with internal cavities and overhangs. This is not possible with subtractive techniques. On the other hand, a CNC machine is capable of doing things that a 3d Printer cannot.
As you mention in your missive, the CNC machine can work on a variety of materials, such as wood and aluminum. It can also typically work on larger pieces than what a 3D Printer can, although with the Carvey this is not the case. Another thing a CNC machine can do easily is make modifications to an existing object. Take for example a bookshelf side that has holes for shelf support pins. You can easily stick this in your CNC machine and program a new set of additional holes that will be the exact size and location you want. Or take a broken guitar neck and cut a clean mating surface onto which a new part can be glued on.
If you peruse several of the longer threads in this forum from members, you’ll get a good idea of what people have made with the X-Carve. This one by Erik Jenkins is quite good. There are also quite a few from Jeff Parish, like this one. It should be possible to infer from these that the X-Carve can be reliable and accurate, but it does require care in assembly and perhaps a certain degree of mechanical aptitude to keep it operating that way. I assume that 3D printers have their own quirks too, although I don’t own one myself. In a recent class I took on 3D Printing, the instructor mentioned that the Qidi is an excellent 3D Printer that is available for $700. In the same breath he mentioned that the heated bed broke on the one they had purchased within a month of receiving it. Your mileage will vary.
Safety… is a broad topic that is not solely related to the machine itself. Are you safe when you work in the shop? Do you use dust control when milling and sawing? Do you keep your work environment clean and swept? Do you wear appropriate protection when working around power tools? The Carvey is enclosed, which should minimize dust and the risk of flying debris, but there will be some dust and chips that escape and you will need to clean the inside of the machine out between projects. A brief check on the Inventables site says that the Carvey does not have a dedicated port for dust collection, but I assume you could add one to it. Personally, if I were milling carbon fibre, I would want one and I would add a small air filtration system in my work area to do fine particulate filtering. But I do not believe these machines pose an inordinate amount of risk over many other machines in my shop. Articles in the 70’s were pointing out the cancer risk of breathing in wood dust generated by sanding and other milling operations, so this is nothing new.
Machine limitations… are predominantly related to the those inherent to subtractive manufacturing. I believe that certain materials, like steel, are not recommended, but with patience and diamond burrs I can’t see why it couldn’t do it. The X-Carve is a hobby grade machine that sells for around $1k. For 10x that price, you can get a similarly sized machine that will cut faster, and perhaps require less maintenance, but fundamentally it will have the same limitations in what it can produce that the X-Carve has.
Noise… I have no idea and I’ve never cared about this. I know that I’m essentially running a router and a vacuum cleaner at the same time when I use my X-Carve and I wear hearing protection when they’re on. My guess is that the enclosure on the Carvey helps significantly with noise, but that you’ll hear noise from the bit working in material, especially when the material is hard. From what I’ve read and the videos I’ve seen, 3D Printers are quieter, but not silent. At a guess, you could probably run a Carvey in an apartment and not bother your neighbors too much.
Shapes… within the limitations of subtractive manufacturing done on a 3-Axis mill, there are no limitations to what you can make with these machines. I encourage you to looks for examples of sculpture and other pieces that illustrate this. People will be happy to show these off to you, as they are justifiably proud of them.
Satisfaction… I’m very happy with my X-Carve. It has exceeded my expectations from the very beginning. It is not perfect, but it is far better than anything I would have cobbled together on my own. The company has been amazing and the other users of the machine make up one of the best Online communities I’ve seen.
Other things… You should have the tools and devices needed to measure material accurately and to prepare your stock. You may be able to purchase much of your material in a form that is machine-ready at delivery, but I imagine at some point you’ll want to move beyond this.
What would be most useful to us on this forum is if you could describe what types of things you’d like to make. Maybe also tell us a bit more about the limitations of your workspace and budget. No one here wants you to make a decision that you’ll regret later.