Hi Les
There is not much difference in the quality of finish or scratch pattern etc. John is right that the red lasts longer, but it is about 30% dearer and doesn't last 30% longer! The main advantage of the white (Plusline) for me is the flexibility. You can fold it and roll it around the shapes you have turned with ease, even in the 80 grit!!
The Plusline only goes to 400g so I have just started stocking the Redline in 600, 800 and 1200 grits too. Not got them on the website yet but to follow shortly!
HTH
Richard