I have 3 Makita-knockoff batteries branded "VANON": two 6AH and one 9AH. All 3 batteries work fine.
The 6AH's don't charge fully on my *old* teal-colored Makita DC18RA charger. I have to charge them on my *new*, black Makita DC18RC charger, and then they seem to charge just as expected. (This could be why some have said they don't have much capacity - maybe they are trying to charge them on an old teal charger. I don't know. Works great for me.)
Other than that, after a few weeks in my construction business, the 6AH's are doing pretty fine. Haven't had to charge them near as much as I thought. The little charge-indicator button works as expected. Use the battery on a drill for a couple days, and it goes down to 2 lights. Charge it, goes up to 3 lights.
Also the stickers on the sides don’t last that long. They get biffed during normal construction use. But I don’t really care about that.
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About the 9AH: This one is physically bigger than the 6AH - it has another row of cells inside it. The 9AH is used to run LED lighting in our off-grid dairy milking parlor. It gets discharged to about 50%, and then recharged 100%, about twice a day. Still works fine after several months. Also, this one charges as expected on either charger (teal or black). This one doesn't have a charge level gauge.
All in all, I'm satisfied. I'd buy more.