I recently purchased 4 x NP-F970 batteries here on Thomann to use with some RGB studio lights. Straight out of the packet, these batteries worked just as good as AC power with my new studio lights. I cannot tell the difference, so that is great. I have used Ansmann products before, and they are good quality.
Time will tell how well they perform after many recharge cycles, but for now they are charging at an acceptable rate - from 30 percent to full in around 3 hours. It should be possible to fully recharge a single battery from nearly depleted to full in around 4 hours using my 1500 mA charger (charging 1 battery at a time). Any faster will reduce the lifespan of the cells within the battery pack (Capacity/5 is a good rule), and these are 6600 mAh, so I am charging them two at a time at 800 mA each. Therefore, as they came with one-third charge (approx. 2200 mAh), it took me only a few hours to completely charge both.
I intend to charge them when they reach about 50 percent capacity, so not letting them drain too much as this would cause the voltage to drop too low. Topping up regularly is probably a good idea for Li-Ion battery packs, no different to when you do the same with your smartphone to maintain good battery health.
Finally, the packaging for each battery is easy to open and the instruction card states that they come with a 5-year guarantee.