This is the oldest one and was introduced to companies in the early 80s. Nowadays it is possible to have this technology shrinked in smaller products that can stand on a desktop. This means that any business can take advantage of it and have a rapid prototyping machine at their service without the need of asking to third parties.
Stereolithography works with special resins which react to light becoming solid. The rays follow the path of the code sent and solidify the small amount of liquid.
Here are the main reasons to pick this as first choice:
precision is higher as polymers are melted together and not layered;
any shape can be printed (no need for supporting materials, bridges are not a problem).
The alternatives to these two major choices for 3D printing are now starting to increase but there is still a lot of development ongoing. 3D printing is also being coupled with different technologies that will get to final users the chance of saving space and budget: the All-in-One Multifunctional 3D printers, just like the FABtotum.
This choice is the best one for people who need a mini laboratory right on the desktop. Normally it is easy to switch from a tool to another and they mostly have the same idea behind: GCODEs, which are the files used for creating 3D printed objects, are a long series of commands that moves the machine.