Top limit switch...why?

Hi all....I have a Mendel90 and a Mendel Max 2.0...they are both great machines, but I was wondering sometime about the Mendel90. the Mendel90 uses a top limit switch, which requires (when homing) a full travel up and a full travel down for each homing exercise. The Mendel Max 2.0 uses a hall effect bottom limit sensor that is much easier to calibrate, as there is no re-uploading of the firmware, testing via two homing travels, and then potentially repeating the exercise. I am wondering why to use a top limit switch?

In the build manual I know it says "to keep the head from crashing into the build plate" but every time I print, there is a long homing wait time that (?) needlessly runs the machine far more than if there was a bottom limit switch.

Anyone know the benefits of using a top-limit switch like that?

Chris has a well reasoned argument on his blog here: [hydraraptor.blogspot.co.uk]

Wow, of course he has a response, he is one of the most the most verbose, and well documented manufacturers I have ever encountered! Thanks for the link. I don't know...I have just been spending a lot of time trying to get everything right, and the other machine went a lot faster with the bed leveling, but I totally see his point, thanks!

The time taken to go up and down doesn't add anything to the build time because the bed is heating while it descends at the start of the build and cooling when it ascends at the end.

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[www.hydraraptor.blogspot.com]

Don't worry about Z travel time - it's a little bit annoying when first playing with machine, but you get used to it very fast. And as nophead said, the machine is heating up anyway during the travel.

Top homing is not as annoying as you think. My slicer's gcode waits for bed temperature first before turning on the hotend. And once bed temperature is reached, the hotend temperature is ready and stabilized once it finish homing and come back down to near zero. The homing duration is essentially pipelined with the hotend.