I'm fixing up an early-to-mid '80s Bianchi ten-speed I found at a garage sale -- my first bike since the MTB I rode as a kid. I plan to mostly use it for errands around town, plus the occasional recreational ride.
I'd like some advice about shifters. The Bianchi came with Shimano Z401 stem shifters (which just clamp onto the stem, so they'd be easy to remove). I also have a set of Suntour downtube shifters from a project bike that didn't work out; the Bianchi has a cable stop at about the right place on the downtube to hold a clamp in place. I'm trying to do this on a shoestring budget, so STI's aren't an option, but bar end shifters from eBay are.
What are the pros and cons of stem, downtube, and bar end shifters, for mostly-urban riding?