I own a '83 Super Course mixte. I am experimenting with various forms. Currently it is set up as my commuting errand bike with a B-67 saddle (I just replaced the seatpost with a newer Kalloy post with more set back) and Albatross bars. Mine has 700c aluminum wheels and I replaced the 25mm tires with 32s. I also own a Bianchi Eros and replaced the veloce triple with a compact double the triple went on the mixte. I really like the bike. I originally got it for my wife to use. While she thinks it's comfortable she is just not that interested in riding. Not wanting a bike to go to waste I set it up for me as a commuter and really like it. It is not a light bike but is a nice road bike. It is faster than cruisers, mountain bikes or hybrids but is not for racing (obviously). As it's set up, it has a nice upright ride, yet blows by the cruisers/mtn. bikes. I am considering the possibility of converting it to 650B wheels and noodle bars and using my B-17 saddle to convert it to a country bike as well. I'd go for it if it's in good shape. It's a nice frame and good bones to work with.

By the way I rather like the stem shifters. It means if I decide to switch out the handle bars all I need to switch is the brake levers. Your other choice would be bar end shifters.