To
fully answer the question you must know all the aspects of battery charging and I don't. There is a standard - CC/CV which is used for evaluating chargers - it's the method of charging. See more here:
Battery Chargers and Charging Methods
"Constant-current Constant-voltage (CC/CV) controlled charge system. Used for charging Lithium and some other batteries which may be vulnerable to damage if the upper voltage limit is exceeded. The manufacturers' specified constant current charging rate is the maximum charging rate which the battery can tolerate without damaging the battery. Special precautions are needed to maximise the charging rate and to ensure that the battery is fully charged while at the same time avoiding overcharging. For this reason it is recommended that the charging method switches to constant voltage before the cell voltage reaches its upper limit. Note that this implies that chargers for Lithium Ion cells must be capable of controlling both the charging current and the battery voltage."
The Xtar wp6 II has this cc/cv standard and the trustfire has a 'near' cc/cv standard according to a few reviews I've seen. There are also reviews on the Xtar (flashlight forums) where there were some that were slightly overcharging - sent back, replaced, etc. etc. ...and with the same complaints with the spacers and springs
Still, they are supposed to be safer.
I've had trustfire 001 for years now without a problem for AW IMR's and other mostly 14500 batts.
I also got a Ultrafire WF-188 Lithium Battery Charger - "good for IMR's" and the negative end hooks were a PITA compared to the paddles on the trustfire. I hated it.
If you want to be 'ultra safe' - get any charger and put it in one of these:
Amazon.com: Li-Po Charge Protection Bag, Small: Toys & Games
