I'm looking into 4 posts right now as well, I have a 2 post from direct lift, and I like it, but I also see where the savings are.
That being said, for the 4 post I can't seem to get solid information about the ramp lengths. On the Bendpak my friend has they are only 20" measured from ramp to floor. The Direct lift lists 36". My car is really low, and it's an important detail to me.
Does the direct lift have 36" long ramps that go up how high"? 5" to get onto the deck?
Also any good pictures of the bridge jack? is it Pneumatic, and require air? or are they more of the pump jack style?