The 3D Hephestos printer from BQ is an evolution of the Prusa i3, and is the most popular machine in the RepRap community. Its mounting is relatively simple thanks to a visual guide supplied. Improvements include cable chains, knurled knobs for easy calibration, and toothed bearings for greater precision. It also includes a Zum Mega 3D electronic board, which offers better heat dissipation and optimized engine control. With Hephestos being open-sourced, you will be able to easily modify and upgrade your machine.