The Orbtronic will certainly be better than the Trustfire. Have a look at HJK’s battery test summary, or his comparator.
Basically any of the 3100mAh Panasonic cells will be good. The cheapest I’ve found are Keeppower, from this seller. He accepted a $42 bid for 4 cells from me ( and might go lower). Got them reasonably fast (thought the seller is away until 19th June).