I have one of the newer models, the EternaLight Xray. It doesn't look as much like a science project as that old square model did, and has some really nice features.
The EternaLight has positives and negatives that make it awesome for some applications, less awesome for others.
The best thing about EternaLight, to me, is that fact that it is dimmable. Along with being dimmable, comes the fact that the dimmer you make it, the longer the runtime. In the dimmer settings, it lasts hundreds to thousands of hours on a single battery change. It's very convenient to take this light as my regular non-tactical light when I go places. I can use it as a night light, dim reading light, all the way up to regular utility use, knowing the whole time that I don't have to bring a change of batteries. This also makes it very useful as an emergency light (if we lose power for two days after the next earthquake, I know I can burn my ET Xray the entire time and still not worry about a battery change). Another nice feature is that on the Xray, there's a fifth, dimmer LED inside the translucent case, that you can set to turn on when the unit is off, so you can always find the light in the dark. All in all, these features make it a great fit for many many uses. And there really is no other competitor to EternaLight when it comes to its coolest features.
The downside is, of course, the form-factor. If you're carrying it in a coat pocket, it's no problem. But it's more awkward to carry in your pants pocket than, say, a Mag 2AA or an Arc LS or an Inova X5, for sure. On its brightest setting, the EL Xray is not quite as bright as the Inova X5, based on pictures I've seen on candlepowerforums. That makes it bright enough for most any utility use for me, but like the Inova X5 and Arc LS, not bright enough for tactical use.
So, if being dimmable and having very long life are appealing to you, and you're willing to forgo pants-pocket carry, it's an excellent light. I suggest you check out the newer models, particularly the Xray Elite, which I believe is slightly brighter than the Xray. I'm glad I bought the Xray, which I got for $35 on the web.
Joe