OK, I do still do the E head mods. The benefit to this mod is its size, or the lack of it. The modded E head on a VG body is tiny. IIRC, it comes in at just under or at 3" long.
As for the performance of the E head mod, bernie might be able to give you a real world use angle on this. He has two models of E head mods and a few A2s, I believe.
From my experience, I can say this. The KL1 on a two cell body will edge out an Aleph II (running at 500mA) in terms of throw, but the Aleph II has all of that sidespill. One of the benefits of the Aleph II is that you can crank the current up a bit, if you feel the need to, to eeck a bit more throw out of the light. With issues of cost aside, the Aleph II is a better all around light.
Now, when comparing the Aleph II to the E head mod, the Aleph II will win out in terms of throw. It's simple, the Aleph II has a 20mm reflector and the E mod has a 17mm reflector. Larger reflector means more throw.
At this point I'll defer to bernie, who has a lux meter to expand on the above statements, if he wishes to.
As a final note, I can say that I carry a modded E head with a NexGen350 LE on a VG body as my "I always have it with me" light. It's small, more than sufficiently bright, and very easy to carry in a pocket. I typically wear a suit and having bulky things in my pockets just screw up the lines in my tailored suits. /ubbthreads/images/graemlins/grin.gif
When I'm wearing jeans or casual pants that allow it, I carry an Aleph II with a pocket clip attached to the switch. When the pants are kind of baggy, I go for an Aleph I head.
What's funny about having the E head mod with me all of the time is that I hardly ever use the Arc AAA that is on my keychain.