Wow, this topic is getting around the forums (presently this here, one on OEM Tech, and one on Street Performance)
Way back in 2000, I popped for a set of Hella E-Code lenses and 100/80 Hella H4 halogen bulbs. Shortly after, I built a relay harness. Very big improvement over stock sealed beams -both in sheer brightness but more importantly in beam focus.
These have migrated to my trail jeep and then to my DD XJ, along the way trying 130/90 (halogen) Hella, 60/55 (xenon) Hella, IPF "Magic J" 60/55, and 60/55 (halogen) Sylvania from the auto parts store. I also bought my daughter a set for her car and my mom a set for her truck (60/55 xenons for both those, then went to 100/80 in the kid's car)
In order of brightness, I'd say 130/90, 100/80, IPF "J", 60/55 Xenon, 60/55. The J bulbs were very pricey@ $75/pair shipped, but also lasted the longest. The others ranged in price from $18/pr to $25/pr.
Recently bought a set of IPF H4 Lenses (#820H), their relay harness (#M002), and a pair of bulbs in 170/100 (#HHC12170100) This full IPF 'kit' cost in the neighborhood of $170.00. Can we say HUGE difference??? I stepped up from low-rung 60/55 halogens - don't recall exactly how I got stuck with those in there, might have given the kid my 100/80s? The difference is pretty amazing. 170w high beams just plain rock. I've only had a couple opportunities to try them out...but the only thing I have used that are brighter/further are 150w sealed beam/clear spot lens KC Daylighters. I may reinstall those KCs using one 100w 'flood' beam and one 150w clear spot beam, and have them triggered off the hi-beam switch.
The jury is still out whether or not the IPF lenses are as efficient as the Hella E Code (on low beam) it seems the Hella might have a little sharper 'cutoff' line, but it's hard to say without a real test (side-by-side, same bulbs, with one lens of each covered with alum foil.)
I will go out on a limb though, and say that I'd put the 170/100s up against any other standard (non-HID) headlight bulb available. Have a 'Battle of the Blinders' LOL
I got my IPF stuff through Rusty at
www.rustysoffroad.com ,
and my Hella stuff from Susquehanna MotorSports at
www.rallylights.com
One thing I found is that IMHO super-bright lights aren't any advantage off-road in the deep woods. Too many weird shadows for stuff to hide in, too much glare for my tastes, and very distracting/annoying to the folks ahead if one isn't the lead dawg.