The Buzz Pro Powerizer RCR123A batteries, and the Infinity 14430 batteries sold by notcigs, deliver just about the same run time, they both test out up in the 620 - 650 mAh range. There's a lot of BS in batteries it turns out, the markings on them don't necessarily come close to reality. Notcigs did a lot of testing to pick the batteries they sell.
I express use in terms of ml because everyone has different vaping style. I generally use 3.1 ohm cartomizers, at about 5V/8W, the batteries last for 6 - 7 ml. If I'm vaping on bare cartos, I use about 6 - 7 ml/day, they last me all day. Another person I know uses about 3 ml/day, they last her over 2 days. When I use a tank, my vaping can bump up to as much as 9ml, then I need to swap batteries in the evening.
I believe the IP, with two sets of batteries and charger, comes in somewhere in the $120 - $130 zone, while the BP with two sets and charger runs about $30 more. I always use the discount code. Given they have the same run time, and have the same internal circuit (they do), it's a matter of personal choice, IP being a thinner but longer mod.
There are lots of good choices out there, from notcigs and other vendors
