Sigh, the battery talk again.
I received my Oasis on May 1st. In the six months I have had it I have used it extensively. I have seen zero change in battery life. None. I know this very well as I put in my calendar when I charge my devices. Don't ask.
So it lasts me exactly the same. So I can extrapolate from that and know there will be no issue. At least not in any reasonable time. I still have my K1 from 2008, I still have my K3 from 2010, I have a basic, PW, some tablets. And a Voyage. Not one of the devices has a dead battery. The K3 still holds the same battery as it did years ago. I don't use it much anymore, but I know when I charge it and where the battery is at that time.
Back to the actual question, what was it again.
I own both Oasis and Voyage. They are both very nice devices. Which one will be a better fit is a personal thing. For me the Oasis is much better than the Voyage as its more ergonomic. So I can read easier. It also has real buttons, again, I can read easier. I can't hold and change pages with one hand on the Voyage. If those are not issues that you think you will have concerns about, Voyage is great. Oasis is great. For me the extra price was worth it to get the Oasis. I use my Voyage still, either when I charge the Oasis, or if I left it downstairs and I am too lazy to go get it. Hence why I always have charged kindles around the house.
The basic with buttons is also a fine device for me. When I am reading on the balcony, its great. Real buttons. But of course they took that away from the line up also. So only device with buttons now is Oasis. And with faux buttons its the Voyage. Both have flat fronts, Voyage has the auto light, if that is something one wants. I couldn't get it to work anymore for me for some reason, after having used it for months.