Renata is also the king of lithium button cells in consumer form factors. A swiss company.
VARTA does the best high-cap OEM batteries for in-ear wearables.
Both VARTA and Renata have quite a range of options for IEC 61233 for medical safety applications. My company uses them for single-cells where we can because they are very consistent.
For AA and AAA rechargables though I always go with panasonic eneloop or ikea rebrands (IKEA allegedly uses eneloops for their branded rechargables) and they have worked extremely well in our laserliner where non-rechargable cells that came with it died fairly quickly.
Their website is really light on details about mAh[0], but Duracell are even worse[1]. I've found a comparison website, but no idea where its getting its sources[2].
Looks like VARTA is around 2400mAh and will last around 5-7 years, whereas Duracell is around 2700mAh and will last around 7-10 years. But let's be realistic here, no battery in the world lasts more 2 years without needing to be switched out. Definitely not worth staying with Duracell.