>>2300231I bought a Thunderbird insert once and it sucked. Maybe I just got a lemon but I didn't get the chance to try out their warranty because the lighter got stolen. I have one of the new Zippo licensed (I'm pretty sure they don't manufacture them) butane inserts and I've had no issues with it.
I'm inclined to agree with the other posters saying Zippos are outdated. These days I pretty much only go on day hikes so my lighters are pretty much only for cigarettes and even then I've moved away from standard Zippos, mostly to jet lighters. I do think it's worth having 1 or 2 Zippos, they're $10 at Walmart and situationally can be very useful in that they stay lit when you set them down and you can use a ton of different fuels. However if you want to buy a lighter and not have to worry about it for an extended period then something more modern is the way to go.