What is the difference with this product and the blue polyethylene riser pipe?

I assume that by the "blue" riser pipe, you're referring to our Eco-Lock pipe? Our Eco-Lock pipe is specially designed, and as such will only work in conjunction with Eco-Lock fittings. The item in question here on this page, however, should be used in conjunction with barbed fittings (similar to most other polyethylene products).