My general rule is to stay away from anything with a *fire label...
T6's are nice emitters, certainly one of the most efficient on the market right now, but they have their limitations as well.
There are two questions you need to consider: 1) what is your use for the light, 2) what do you currently have in terms of your battery/charging loadout?
1) can generally be answered as either EDC, or other special uses such as LEO work, outdoor activities, S&R, etc.
2) is usually either AA or CR123 for most people, but this can also include whether you've invested in Li-ion RCR's as well vs just primaries or nimh's.
Regardless of that, I'd also recommend you consider a T5; they have a much nicer tint and I find them to be more usable than T6 based lights.