I have a first gen 12.9, use it 4-8 hours a day at work. My only issue is that I went through 3 smart keyboards, since they stopped working after about a year. I am hoping that the new folio is better...But, the Pro is great, but I can almost literally watch the battery indicator % drop when using, just for split screen with OneNote and email, which is the preferred configuration. Assuming that I have charged this at least 1 per day, that means over 1000 charges adn I am OK with that. I will be getting the new 12.9 next wednesday, and will post any follow ups!