Looks is a big part of it. But caveat emptor: buyer beware! -- the SW02 is quite pricey. On a whim I bought a pair of them when they were on sale at Gander Mountain for $25, lowest price I had ever seen. When I started using it however, this is important, the switch body is so large I had significant difficulty operating it one handed with the thumb. I had to slide the light back in my hand to get the thumb right on the switch, it was awkward at best. Compared to the straightforward Z49. I stopped using it becuase of this, even the momentary button Z48 was easier to use. Then I found a home for it where it worked best: on my U2. Somehow the way I grip the U2 it works for me. Whereas the Z3 or 12ZM I had to move my grip to the back of the light, imbalanced. For momentary activation the grip shifting was annoying enough to stop using it. I personally dont care about this, but if you are one of those "My HAIII HAS to match and be uniform" folks forget the SW02. Even on the switch body its a two tone affair, the dashed ring is different from the large scalloped grip, and totally different from my lights, just enough to be noticeable. I actually like the shade differences, it accentuates the lines. But my primary concern is always functionality, and in that regard you want to be sure you like its fit and function. I like the guarded tail, but the guard with the large grip in front of it can be a tad daunting for momentary use one handed. Just my 2 pesos. Enjoy the light! IMHO you are thinking too much about this. Jump in the water, my friend! I think the 12ZM with 3" head is a killer host for the Arcmania SFTM but to each his own. The KT head is VERY heavy and lesser performance than the SRTH or three inch T1/2. Speaking of this I have to track down a new SRTH....
