I didn't see the size posted on that Serfas but it looks like it would be a bit more bulky than a typical single AA mini torch. The one I posted is about 93mm x 17mm ( diameter ) or about the size of my middle finger. It will tail stand and uses a clicky switch on the tail. The Serfas might make for an interesting commuter light but I don't think I'd like carrying it in a pocket as an EDC torch ( which is what the OP wanted )...

Anyway, if I was going to carry something a little bigger/brighter I'd go with a single 18650 cell torch like the Convoy S2. I have one similar to the link I posted only mine is gray and has a custom driver. The S2 is relatively small for a 18650 torch but very bright. It has no sharp edges to make holes in your pockets. Makes a great back-up lamp for your bike as well. Dealsmachine has several variations of the Convoy with different drivers. I bought and had mine custom built at Mountain Electronics for about $35. The one I linked to at Dealsmachine is about the same thing as the one I own ( except for the emitter and driver ) only the body is blue on the one from DealsM and about half the cost. ( note the DealsM. one is using a neutral white emitter which is great for natural terrain )