I have one of those "Venom" batteries for my P2V. It's 6000 mAh and it's my favorite battery. The last time I charged it (which was after a 3% deep discharge), it showed literally zero cell deviation (0.000 deviation between any cell). All the cell voltages (all four digits shown for each cell) were exactly the same when it turned itself off after charging. A coincidence for sure, but still...
I also LOVE the screen. It's very bright and can easily be read in the field. It can even be read while in flight if you bring your craft in close enough. No guessing as to your charge percentage. Clicking the button reveals a second screen showing the cell voltages of each individual cell and a host of other battery info.
Many experienced Phantom owners say buying a third party battery is risky at best and crazy/stupid at worst, so know that before you buy.