I used to use the Calder Valley Greenway (Sustrans) to commute between Huddersfield and Dewsbury. It was traffic free and tarmac'd all the way, so was ideal. It also cut off a big corner and a nightmare of a roundabout and junction. The only time I wished I'd avoided it was after a hard frost, when I went barrelling down a slope out from a wooded area onto an exposed bit of path, and was just saying "Ooh how pretty" when I realised the sparkly bits were ice on the tarmac and I was flat out on overinflated knobblies. I needed to scrub off speed and dragged my back wheel about twenty yards before the front gave way and I ended up in the brambles laughing like an idiot.