garage lighting question

Hi guys,
I have an oppertunity to buy some metal halide lights.
They are 400 watt multi-tap 120v - 480v $35.00 a piece complete.
I have a 24 x 24 ft. shop with a 14 ft. ceiling that needs lit,
would these be any good for this purpose?
Any pro's or con's to these lights and how many would be needed
to light this shop well?
I have a choice between hanging or wall mount or would some
other type of lighting be better?
Thanks,
Carl