Longevity and price are a important factor when you can buy a Bridgy rear for only 162 bucks. except for the deal on left over Metzeler's they are a pricey tire. As for the front well Avon over Metzeler any day of the week.
I do prefer sticking to radials on a bike made to ride on radials, though, speed rating isn't that important to me either tbh. Not that modern bias tires suck, but they do still have the drawbacks of bias vs radial. Since great radials for these bikes exist, I don't see a reason to run bias.