I don't know what kind of tailcap you got, but if you got a Z52 (momentary/twistie) I'd like to cast my vote for the IMR-E2. It's a whole lotta light in a small package. That'ts what I got for my EDC. I know, it's a big sacrifice in runtime, but that's why I carry LED lights on my keychain.
I just ordered one for my E2e. I've been meaning to try one out for awhile. The EO-E2R is very bright, but sometimes I like to EDC a pocket rocket. In the beamshots I saw awhile back, it smoked a P91, which is no small feat. I don't remember what the P91 was running on batterywise though.
The sacrifice is no big deal to me, especially when I'm traveling in my car, as I have extra batteries, a couple spare EO-E2R's and an E-series extender in the glove box. If I need more runtime I'll pop in more batteries, or if I really need more runtime I'll put in the EO-E2R and run it off of three primaries in which case I'm looking at a good 90mins to 2hrs per battery set since the EO-E2R only draws about 800ma. Need more than 2hrs? I'll put in some more batteries..
Plus I have a 6V Energizer lantern light in the console, and since I got my Sunlite Slim 3W warm tint 100 lumen 3AAA light the other day, I've been carrying that in my coat pocket too. Doesn't replace my incans, but it's a hell of a nice little light.
Yea, I run the Z52 style twisty on all of my E-series. I have just never been a fan of the Z57. Probably mostly because it looks ugly to me. The latest variations of this clicky are very reliable though.