As a long time Sony user, I can highly recommend the Kobo Aura H2O. The H2O fills all of your must-haves.
- The H2O has an eInk Carta screen. It's has much better contrast and significantly higher resolution. Very nice.
- It's lighter than the 950.
- It's actually a larger screen at 6.8" because of having a proper aspect instead of just stretched.
- Using Calibre, you can have collections made when eBooks are sent to the H2O.
- The battery life is very good.
- It has a much newer version of RMDSK (ADE) than the 950 for ePub compatibility.
- You can read ePub from Overdrive with the H2O.
- It works very well with Calibre.
- The front light is very nice to have instead of a light cover that adds extra weight.