Re: the snowflake, the argument that I've heard is that the spokes are longer and thus have more spring to them. It's a squishier wheel and not as stiff, so it absorbs the impact. But like I said, I don't think anyone's actually tested that.
As for tied-and-soldered, it's been hashed and rehashed. At the end of the day, the spoke junction is immobile even without tying and soldering it. There's no measureable improvement.
http://www.sheldonbrown.com/brandt/tied-soldered.html
http://yarchive.net/bike/tying-and-soldering.html