NSTs that ever made their way into my hands:

Allanson 15000kv/60ma This lasted for months before finally frying. The conditions under which it bit the big one are still under investigation, as the safety gap roared at 60Hz non-stop and the spark gap barely ever fired. This was AFTER the spark gap was shortened by two gaps. One of the HV windings shorted out as the NST was being powered down on a 1000W dimmer switch. It's currently sitting in my freezer awaiting a hammer and chisel.
Franceformer 15000kv/60ma This also lasted months, but was never used in the tesla coil, so that's why. It died one night when I went to add it WITH the Allanson NST to my tesla coil. I removed both NSTs from teh tank circuit and began to test for the phasing to be on sync. It wasn't and the Franceformer gave up almost instantly. TOO quickly, in fact. One of the HV windings now refuses to put out more than 1000 volts, but still at a high current. Carbon tracking? It now also sits in the freezer, naked and inoperable. Interesting note: This NST has mica just inside the case side, running parallel to the axis between the two HV insulators
Allanson 15000kv/30ma Still works for now.
Allanson 15000kv/30ma with PFC Was nice, if a bit heavy compared to other 15/30 NSTs. It died just like the 15/60 Franceformer. This thing just completely dead. No 60Hz hum, no ANYTHING from the HV windings. I haven't bothered to test to see if it's drawing any power yet. I'll start going over it with a multimeter soon.
Franceformer 15000kv/30ma This unit had one of the HV insulators broken off during shipping, so I was able to pick it up for free at a local neon sign shop. I dug out the broken HV lead and soldered a length of GTO cable to it. Works great!
Transco 15000kv/30ma Still works for now.
Transco 12000kv/30ma Still works for now.
Misc. 12000kv/20ma Can't remember who made this...but it works.