They’re good enough; but when you consider the price, they’re amazing. They’re certainly not the brightest, but I haven’t tried running a 14500 yet. Since you mentioned it, I’m eyeballing some LiFePo4 14500s; but the typical 500-700mAh capacities are a bit disappointing. Surely it would be much brighter, but at only 25% of the runtime. On the other hand, I can get [4] of these batteries for like $10 and they’d last over 5 years and 1,000 cycles. Plus they could be easily charged in series with a little solar panel I have — if necessary.
I’ve bought one of these 5-packs and one of the Kootek brand 5-packs at various times. I have a flashlight at the ready in pretty much every conceivable spot around the house and car. They also make great gifts to pass out at kids’ birthday parties or whatever. Cheap as hell and very useful - my favorite attributes.
All of mine have worked so far. No duds yet.