Oooh how I hate to be wrong, but I guess I have to admit that the Pocket Ti stove is about a half-ounce lighter than the FireFly (at least if you don't use the tin it comes in). I had not found this stove when I did my research on woodburners, so I guess the FireFly is only the second lightest. I don't know how long the Pocket Ti has been available, but the current site lists it as a 2012 stove, so it may not be that long. The Pocket Ti appears to have achieved this even lower weight by having an open side/door and probably by having a smaller sized firebox overall.
Snide comment alert: If you watch the video on the Pocket Ti, the ability to use multiple fuels is nicely demonstrated, but it's also shown in the video that the addition of an Evernew titanium trivet to the top of the stove helps create air space between the top of the stove and a pot (if you like a squat pot like I do) and improves draft and performance. The trivet weighs 16g and costs an additional 12.99 pounds. With this modification, the Pocket Ti would probably draft as well as the FireFly, weigh as much, and cost more. Good to get that out of my system.
Anyway, at the risk of encouraging dissent, here are some of my thoughts on woodburning stoves in general from having made and used many of them over the years:  ignoring stove weight for a moment, a larger firebox makes a stove easier to light and easier to keep going;  you want a good air inlet under your fire and a good air exit above your fire but under your pot. So the trick in making a light woodburner is to satisfy #2 while making the firebox as small as is reasonable (but not too small) out of the lightest material you can. Titanium is what works best as a material, but adds expense (Oh well). The current size of the FireFly is as small as I would want to use myself. I could make a smaller FireFly, but it would be less stable in use and harder to keep going because it would not hold much wood. A 2/3 size FireFly would save maybe .75 ounces but would not work well IMO. Your opinions may vary.