My Mendel90 is on its last legs - these are the things about it that kept me using it for as long as i did as well as what needs to change with its iteration.
http://www.youtube.com/watch?v=M8BlJ_8nD68
@Mark_Rehorst not at all - the Z-axis motors are wired in series, so I’m getting full holding torque there, and the Y-axis additionally resyncs itself once the motors are turned off.