I've been using the Eneloops since April of 2006, no problems to report, even with high temps in three summers (two here in the USA, one in Brazil). Perhaps the competition they refer to are the normal Ni-MH batteries. Anyway, I'm not sure if these Imedion batteries are a slight different formulation from the Eneloops (likely) or a rebadge (less likely but possible). The Eneloops have not increased in capacity since inseption, staying at 2000mAh. But it sure is nice to not have to recharge batteries just because I did not use them for a week or so.