Which X Axis drive arrangement?

Hi
I am looking to get a router probably x600 x y400 x z100 or thereabouts. Having searched some options there are a lot of USA units but shipping and CE etc may cause issues.
What I would like is peoples experiences/knowlegde with the different X axis drive methods I have seen from European manufacturers

1. Central screw driven by 1 motor, restricts cutting below the machine (ie placing on large panel)

2. 2 motors on the X axis driving each side, looks like lost steps would cause racking?

3. 1 motor on X axis to one side with a belt driving another screw on the other side, torque may be an issue driving 2 screws with one motor

All these configurations can use either rails or rods for the main support but it is the drive method that interests me.
Any help appreciated