At the time of writing I’ve just received these batteries so I haven’t actually been able to test them yet (waiting for my normal batteries to die first). I’ll update this section when I’ve been able to form an opinion but from what I’ve read about them it seems promising. It should also be a lot cheaper than chewing through normal batteries at the rate I’ve been doing.
Update: I’ve now had a chance to test these batteries for a while and all I can say is that they’re way better than the cheap ones I used before. The seem to last a lot longer, recycles the flashes faster and I won’t have to buy new ones anymore. Definitely recommended.