Is Minix more robust because it is microkernel?

In 2006, professor Tananbaum released Minix3 with a new book [15] and papers [14], [9], [8] supporting that drivers running as processes in user mode made Minix, a microkernel operating system, more reliable than monolitic operating systems. We tested Minix3 in a operating system course at São Paulo University and unfortunately, we reject some statements of professor Tanenbaum; however we claim Minix3 as a powerfull educational tool in operating system courses.