IMO, Hamilton is a great brand, but I am aware of some that have tried the XM's with equal or greater satisfaction... none I'm aware of regret their decisions to try the XM's and seem to continue to use the XM's for an "equaled" satisfaction for a lower cost. I will remain loyal to the SE XM's and will begin to use the XDE when they are able to improve their design... until then, it's AB, BLV, Hamilton, or Ushio for the DE bulbs. BTW, if you're gonna change types of bulbs, make sure your ballast will fire them properly.