Do You Need the Older Lens? Tamron 20-40mm F2.8 Review

"But what about the Tamron 17-28mm f2. 8?" I asked our rep over at Tamron. Apparently, the Tamron 20-40mm f2. 8 Di III VXD lens isn't replacing the older optic. Instead, they're kind of, sort of, complementary to one another.