I've had my Z-Plus for years and it still works like new. I've had my Thunderbird insert for a couple of months and am quite disappointed with it. For those who don't know, on the bottom of the insert, there is an flame adjustment on the bottom that is turned by a small flat screwdriver. When the insert is full, I need to turn the adjustment screw to the low setting to keep from getting a six inch flame. Every few uses, I need to pull out the insert, and turn it up a bit just to get a usable flame. Every few uses, I need to pull out the small screwdriver on my SAK, pull out the insert, make the adjustment, and then reinsert it into the lighter body. It's quite a pain. BTW, I am using Vector butane. Maybe I just got a bad one. If it worked like I expected, I'd love it.