Andrew
I bought an SX2P last spring and I haven't had any issues with it. I presume your referring to rack and pinion arrangement that raises the head up the column, I would agree with you that it isn't ideal, but I haven't found it to be a problem in use. I do plan however to do a gas strut mod in due course. In my opinion the brushless motor and R8 spindle taper are major benefits, the other one is of course the fixed column, once it's checked for verticality, you'll not need to bother with it again. The tilting column on the WM14, or indeed any mill is a source of potential error you can do without. It's also very quiet in operation, often the loudest noise is the cutter against the work piece. I would seriously suggest you look at the SX2P again.
From an impartial point of view I have bought items mainly from Arc, but also odd bits from Warco, but not a machine, so I can't comment on their service though I have no reason to doubt it, I can say the service I've had from Arc has been superb.
Regards
Martin