i think they are good lures, and i had a nice keeper steal mine (mackeral color) on the first cast using a silver colored leader.
you have to jerk them hard to get them to dive at first and sometimes i stick my rod into the water to alter the dive angle because the lip or angled mouth isn't that large so they run semi shallow as a floater /diver style lure. here's more info below.
http://digitaldagger.com/plugs/yozuri1.html