I LOVE Shimano external BB's and cranks. For function, they can't be beat. Basically essential equipment for mountain bikes for me, although ISIS was pretty good. I run 'em on my mountain bikes, cyclocross bike and my wife has one on her roadie for the compact chainrings. Mine look good on their bikes cause they're modern; hers are on a 80's Marinoni and they're shiny shiver Tiagara so they're passable.

The bearings don't last as long as most internal styles.

I don't ride road hard enough to worry about the benifits of lighter, stiffer, faster so I stick with the vintage kit, including the BB/crankset. 7402 works for me.