I vote H2O.
Good things about the H2O:
- Travel friendly design - the bezel is raised above the screen. This means that with the reader enclosed in its sleep cover, anything squeezing up against the reader will only put pressure on the bezel - the screen itself won't be touched at all, most of the time. This makes me feel much more confident traveling with the H2O, especially when my bag is tightly packed.
- Waterproof flap also protects against dust: on a similar travel-friendly level, the microSD slot and micro USB socket are covered (on the 1st edition) with a flap. While the durability of the flap may be a concern, it does offer the advantage of protecting against dust and other bits that may get stuck.
- The screen is more responsive and accurate.
Bad things about the Aura One:
- Uneven, distracting "natural light" setting. I love the idea of reducing the amount of blue light coming from the screen. But not with green blobs at the bottom of the screen. Some people report not having these green patches of colour, but it seems like such a common problem to put me off bothering dealing with Kobo's customer service and waiting for the multiple replacements I'd need to finally get one with a consistent and even "natural" light setting.