Z axis on the knee, how practical????

Group,

I've been following the discussion of Z-knee conversions. I
understand why this is done...because it's easier than fitting a ball
screw to the quill.

My question involves what it's like to machine parts on a B'port or
larger machine with the Z on the knee. Personally, I can't imagine
it would be a desirable situation. First off, sometimes I lean on
the table as a part is being cut, that wouldn't be possible with the
table moving up and down. How about part visibility, isn't it hard
to closely watch the cutting action if the part is moving up and down?

So, tell me what it's like. Are you guys who are doing this type of
conversion experienced with more conventional Z axis (quill) machines
or don't you have any basis for comparison? Maybe the Z-knees move
so slowly there isn't a problem?

just curious,

Doug