The Xenon bulb on the Streamlight 1L and the Arc LSH-P are about the same brightness, but the Arc LSH-P definately throws farther because the HD/NX-05 combination makes a tighter beam than the Streamlight's 1L faceted reflector. You can focus the beam on the Streamlight 1L, but the tightest focus isn't that tight.
If throw is your main criteria for an EDC, the Streamlight 1L wouldn't make a good candidate, especialy if you weren't satisfied with the Arc LSL; which might have a similar beam pattern since it is a low-dome.
The Streamlight 1L is cute and small, but it isn't as small as the Arc LS, it is actually considerably larger lengthwise and in diameter. It is also heavier, but not by much; but since it doesn't have a pocket clip, it is more likely to thrash around more in a loose pocket.
What i really like about the Streamlight 1L is the dual level output. The LEDs are REALLY usefull. I find myself using the lower output 85% of the time. I guess the Arc LS has a similar feature, but only in moon mode. Sometimes 15-18 lumens is just too bright - the 1L's lower output really helps in those situations. However, the switching process is sometimes very annoying. When you turn off the LED's, the next button push will turn on the brighter Xenon lamp. So if you are working in a situation that only needs the 3 LEDs, turning off the light during an operation means you have to first cycle through the xenon lamp before you can access the lower output. This is very tedious when all you need to do is flash something very quickly... too many button pushes. But, i'm not really complaining. I think it is very innovative, if not revolutionary, that Streamlight made this dual level flashlight. I know that this type of technology has been used in headlamps, and in the Surefire A2...but for something this small and for 20 dollars... you can't really complain. /ubbthreads/images/graemlins/grin.gif
I use the Streamlight as an emergency EDC in my backpack. It really helps in my college classes that frequently turn off the lights for overhead projectors, slide presentaions, and movies. My Arc LS is very destracting in class, so the LEDs in the 1L are just perfect.
If you want this kind of performance in an Arc, you can wait for the LS4...it will cost you MUCH MORE than 20 dollars though. /ubbthreads/images/graemlins/grin.gif I think it's worth it.
If cost was a concern, and you REALLY must have the dual output, spring for the Streamlight 2L. It is still big, and doesn't have a pocket clip, but if you want power and throw, this is the light for around 30 dollars. I guess you can try carrying it in a belt holster if you find it comfortable that way.
..I'll try taking some comparison pictures for you tonight.