I have the ductile iron #4 and really like it. It's heavier than a Stanley but it's never seemed like a big deal to me. The bronze is heavier, supposedly.
I don't like A2 either, so I replaced the LN iron with a Hock O1. This requires a bit of filing on the chipbreaker slot. Not a big deal, but I suppose most won't like the idea of replacing the iron on a brand new $300 plane.
I would favor the LN over the LV for a smoothing plane due entirely to the adjuster. The Bailey adjuster is the only one I know of that is actually an improvement over just tapping the iron around with a hammer.