The primary purpose of 3D pens is to draw 3D artistic objects or not. For this purpose, molten plastic is used which it makes possible to construct objects in relief; the principle remains the same: We heat the plastic to melt it and lay it in the way we choose to build an object. The characteristics of the product may however vary and how to use it with, let's see together these additional features:

The type of control: The performance of the 3D pen can be improved with the temperature and speed control of the 3D pen. Indeed, by modifying the flow velocity, it is possible to spend more time on precise details and less time on the repetitive parts of the drawing. The temperature setting makes it possible to modify the overall experience of using the 3D pen; this allows creating new more realistic textures for your 3D drawings. This kind of smart controls are what is missing today's pens, and I'm sure about what the builders will be making improvements to in future releases of 3D pens.
The design: The design of the 3D pen may seem to be an unattractive item to look for when buying and yet it is one of the most important parameters of your purchase! Indeed the shape and the materials used to manufacture the 3D pen will not only influence its look but also its performance. In fact, a thin and light pen will be much easier to handle and use to make drawings more precise and detailed. The first generation of 3D pens was a bit complicated with their exaggerated size and weight, but today it is possible to find very fine and light 3D pens such as LIX smart pen or 3Doodler 2.0.
The type of filament: As you know there are different types of plastics usable when drawing in 3D: ABS and PLA. These 2 types of plastic have different melting temperatures and are used differently (the difference in more detail below). However, both types of plastic are not the only variants of filaments that can be found. There are dozens today and the easier they are to use (Easy filament change) the more they are appreciated. There are four broad categories of filaments: Standard, Flexible, Composite and Specialized.
The brand: Although it is necessary to look at the models, in particular, it is interesting to be interested in different brands also. 3Doodler is the pioneer of the 3D pen, and they have a certain technological lead over other companies on the market. Scribbler offers a 6-month warranty to put all its confidence in the product. The LIX brand is one of the most innovative, constantly testing new concepts. When a new high-tech product of this kind appears it is often copied by unscrupulous Chinese companies on quality. So yes we find 3D pens less than 50 €, but I advise against them in general ...check lix 3d pen reviews
Customers' opinions: We live in a great time that allows us to communicate in an instant via the internet, why not take advantage of it to choose your 3D pen? People who have purchased 3D pens on Amazon often leave a customer review to give their opinions on. It is interesting to look at the average notes to get an idea of ​​the performance of the 3D pen. Be careful though not to fall into the trap of customer reviews: 3D pens are completely new and never seen before, customers who buy them are often as you and have never tested another 3D pen of their life. The judgment of these people is therefore biased, and a person who bought a cheap 3D pen does not have the same expectations as a person who bought a high-end product.
For a particular it is often idiotic to buy a 3D printer, they develop at a crazy speed, and their prices are still way too high for individuals. The solution is in 3D pens that make it easy to create small 3D objects.