Well, an extra controller is useless in my situation. I play alone.
And my batteries have been holding charge for a couple years so far, it's been good with me...but yes,
I don't use eneloops, but I'm sure they are great.
My experience with MS charge and play was horrible. I had to play with the cable constantly attached to the controller after less than a year because the battery wouldn't hold a charge. Maybe MS is using better components in the kits now, because by 2006, 2007 they were a piece of shit.
If you don't want another controller then I guess going with rechargable batteries or an extra controller is pretty much the same thing, since both could be considered "hidden costs".