Eneloops are great for wireless mice with their extremely low self discharge rate, they're what I use in mine. That's probably why Apple sells you 6 - there's always a fully charged pair waiting for you even if you charged them weeks ago. I figured they must be Eneloops from the announcement, it's a good thing IMO
I use them (actually, the new apple ones) for my wireless guitar transmitter. Gets about 7 hours or more on a single charge. The only downside, is that devices that have a power meter calibrated to alkaline batteries show full charge until about only 1/2 hour remains; and they show 5 minutes left (red blinky light) when there is really about 1 minute.
But with wireless transmitters used for performance, I put newly charged batteries in before each show, and have 4 spares (it takes two for a Line 6 G30 or G50).