Pics I've seen pics of two TF carriers show cracking failures.....one cracked weld, one crack/tear in the metal itself. This is of the carrier unit itself, not the cast hinges.
Looking at what info came with the pics, one guy, may have, dropped off a rock shelf and hit the spare tyre (no idea how much force went through the carrier weld).....the other guy, it would appear, didn't follow the instructions about the side supports which dampen any vibration of the heavy tyre (the two round black plastic crush tubes on each side of he carrier). This guy had fatigue cracking through the carrier metal itself, which I personally think were caused by the heavy tyre vibrating.
There has been a design change since the first "broken weld", I'm told there were other instances, but I have no info on that.
TF apparently wrote off the latest tearing failure as "improper install", which may well be the case. I haven't heard of any other instances of the same type of failure.
There is a lot of finger pointing and bullshit going back and forth on various US forums about the subject.......... I looked at the pics and original posts and tried to take the info from there.
The TF carrier is made in China, I believe the same product is also sold under another Jeep parts supplier's logo......not sure who's, I saw it mentioned in a post about the last SEMA event - maybe Quadratec????? Not sure.
Smitybilt do an oversize tyre carrier kit. Have no info on how these units work on the JK, except I've got an XRC Atlas rear bar and carrier on mine which seems fine.
http://www.smittybilt.com/product/index/189.htm
And a couple of companies in the US offer HD hinges to replace the factory rear tail gate hinges.