I have 24 64's with the medium flood kit and 4 46's with narrows (for a neat ACL[ish] effect). The 600 watt DYS kit cuts through the fog really nicely even with blue gels. The lighter weight makes it nice and easy to carry, especially when you have several in cases. $5 per lamp isn't bad either.
Two drawbacks: the beam pattern is wierd, works fine for back light, not cool for front lighting. Lamp life, after you pass the lamp's life expectancy, you can really really notice the drop in color temp. If you are going to use gel, don't get narrow kits, your gel will burn in little time.