Mine came with the van. I wouldnt buy one given the option.
Theyre a great idea but for us they're not up to the requirements of the job. I've bought a double ladder-slide roof-rack for £520.00, saves so much hassle with bungees or those threaded clamps. Slide the ladder on and clip the strap shut. No scratched paint work from all that manhandling around the side of the van and no standing on the front seat either trying to strap it on.
I was hoping to get £300.00 for the Ford rack so £455.00 is a result. It means effectively Ive only paid £70.00 for the ladder slide.