After a few years, I thought it was time to retire some of my old Sony NPF-970 batteries. You start to notice that they won't hold a charge as long, and taking them out in the field was always questionable. After shopping around, I stumbled on to the SWIT S-8972 Batteries. The only Sony NPF style battery I know with a built in meter! I can't tell you how something so simple could really make life a whole lot easier.
Ok, so the battery meter is huge in my book, but there's more to the SWIT S-8972. It also offers a DC output allowing you to simultaneously power another device. Do you even know how many video devices there are that could benefit from this? Maybe you've got a monitor that runs on Canon LP-E6, but now you can optionally power it with the SWIT. An LED light? Audio recorder? Or how about taking a Sony Dummy battery and using the SWIT as your power source to power your Sony A7sII A7RII (or compatible sony camera).
In any case, you could buy cheaper batteries and i'm sure they will last a good while. But for a few more bucks, I find the built in Battery Meter and 7.4V DC Output is worth the extra cost. You can find the SWIT S-8972 product page (here).