Got my bike back just as the LBS was closing today. No one around to talk to about the differences in the two wheel sets. The old rims are 559 x 21. The new are 559 x 19, so a bit more narrow. I don't know if I am going to be able to easily swap them back and forth, without adjusting brakes or anything. If not, I just blew a hundred bucks.
Went for a ride on the bike to test the new chain, cassette and new brake pads. It felt pretty much the same.