I am a big flashlight guy including collecting some vintage stuff. Have a nice collection of Vintage Big Beam Lanterns beginning with my Father's original 1956 Big Beam 164 and a 50's vintage 166 in the box. All mine are pre-Teledyne made by U-C in the good ole U.S.A.
Big Beam 164
I have found that Mag Lite makes about the best for the $, now that is not to say that stuff like the Surfire does not exceed the Mag performance but it is also a huge price difference but sometimes may be warranted with tactical light needs.
All that said there is a very small hands on owner operated company called Malkoff Devices, Ltd. Gene Malkoff is a super guy and produces major league upgrades for many lights that includes some unblievable LED systems for Mag Lite products. Most of the time there is a waiting line for his more popular upgrades but you can get on an email notification list for when they come available. I have his LED Upgrade in a couple of 4-cell Mag Lites and holy cow are they impressive.
Check them out:
http://www.malkoffdevices.com/