These unique 3D printer designs might surprise you with their new twist on the typical.
Delta systems are typically known for their use in pick-and-place machines. They are precise and fast. Several people have adapted this to 3D printing. You can see that, even though they are delta robots, they can use very different construction and driving methods. Some, like the RepRap Rostock (shown here) are belt driven and have a huge vertical build volume.
The RepRap Simpson (shown below) is a completely different design but appears to work as fast and precise as possible.