Before I got my present job I worked as a service tech for plastics extrusion machinery manufacturer in McPherson Kansas for 16 years. I can tell you that the vinyl siding is only as good as the company that manufactures it. Some companies cut corners in the manufacturing process and it isn't worth a damm. Others like Certainteed seem to make quality product. The siding will fade a certain amount over the years. It will also get somewhat brittle over the years and will not withstand hard hail storms very well. I would recomend if you get siding you get a extra box and rat hole it somewhere. This way if something happens to one piece you have a replacement. Like a kid hits and breaks a piece with a base ball. After a few years the new piece will not match the faded siding but in a couple of years you won't be able to notice it. The reason to keep some spare siding around is do you really think in 10 years they will still be making the same color and style of siding? I think not.