Well, I haven't used the Trail Designs one. I made one several years ago out of some aluminum foil, though. Like the older BrassLite stoves, shutting off the vents really helps to cut down heat output. Generally around 20-30 minutes burn time compared to 12 minute burn times. No, it doesn't save any real quantity of fuel, maybe a gram or two under some conditions (higher environmental temps.)
I also played with another one made from a ring of a soda can. Make the ring, then cut it seems to work pretty good.