Over the last few years, I have bought a lot of NiMh rechargeables, with mixed success.
The only two makes of batteries that have lasted have been some GP batteries (green and orange) that I have had for over 6 years, and still perform well, and some I bought from a reputable battery company.
I bought some "Tenergy" (blue) that perform reasonably, and have been relaible
My first bad failures were BST, that very soon didn't take a charge, lost charge quickly in storage, and didn't last long in use. Despite a load of hype from the seller. When contacted several times, no reply was received from the seller.
The worst ones were Sinica (green and silver) About a third of them wouldn't charge when new. Although the seller did replace some, I ended up with less than half the batteries I paid for.
Recently I bought some BTY batteries (blue and silver), these don't seem bad, but are probably around 1500 mAh capacity, not 2500mAh as stated.
But as far as the ultimate scam goes, the prize must go to some lime green ones I just bought from China. They have no brand name, just writing and a recycle sign on them. These last about a quarter the time that a good 2000mAh battery lasts. Today I thought they felt rather light, and weighed them. They weigh about 15g each. This compares with 25g-30g for the ones that work well.
My conclusion is that it is impossible to know how good a battery is until you get it, so therefore buy locally (ie for me from the UK), buy a well known branded name, and test them, if after a few charge/discharge cycles they don't seem to be performing as they should, contact the seller without delay. Don't leave feedback until you have tried them, and don't leave negative feedback unless the seller refuses to help.