I always recommend buying from a reputable dealer. I have been pleased with Efest. Another one I have had good results with is Keepower, but I have recently read they are a "re-wrap", but so far all their cells I have used have lived up to expectation. The Ultr*fire cells and similar names seem to be the most counterfeited. I'm sure many others will share their opinion and there usually is a "common consensus" that can be a reliable guide.