They will thrive in the the Oregon Willamette Valley.  The seeds that are used in these mixtures (likely fine fescues) are produced here.  That is why we call Linn County the "Grass Seed Capital of the World".  

However, you should expect to have a lawn that looks like a prairie, pasture or grass seed field.  The grasses grown in the Willamette Valley seed fields (perennial ryegrass, tall fescue, fine fescue, Kentucky bluegrass, etc.) are the same we plant in the lawn.  When you stop mowing your lawn it will grow tall.  I think the name of the company (Prairie Nursery) is very indicative of the result.