Well, I'm not personally a fan of plastic lights in general but I've owned the Streamlight and the eLED. I traded the eLED and gave the Streamlight away. Both were very decent lights though.
In general, the eLED and Impact XL are in the same class... not much throw, decently bright, very good runtime. The Streamlight has very nice throw, is brighter than the other two but half or less of the runtime.
For an indoor light, I'd go for the UK or PT... For an outdoor light where I might need to use it beyond 20 feet or so, the Streamlight would be a much better choice.
Just depends on what you are after... throw or runtime.