The battery performs well. I ran our 90-minute test video, with the screen set to full brightness and apps updating over Wi-Fi in the background, and in that time the Meizu Pro 5 Ubuntu Edition dropped from 100% to 87% charge.
That's a loss of 13%, which is about right for a premium high-end smartphone; in fact, for such a large screen it's actually quite impressive.
You'll need to be aware that using two SIMs will have an effect on battery life, but I quite like the fact that you get a decent amount of flexibility with regard to which SIM is used for what. You can, if you like, bump one down to just voice calls on 2G, to save power, and have the other SIM blasting through 4G data.
To save power beyond that there's an auto screen brightness option and, erm, that's mostly it. As I say though, there's no noticeable problem here, and I got a day of use out of the phone. Perhaps having no apps is helpful in this regard.
I have to say that the camera in the Meizu Pro 5 is a bright spot – photos from the rear-mounted, 20.16MP snapper are actually very good, save some minor focusing hiccups that are likely just teething troubles as I get used to the interface. I like the fact that colors aren't overblown – they feel natural and realistic.
Low-light indoor shots, taken at dusk with an overhead light on, are solid enough. Detail remains solid, with lots of sharpness to give photos that all-important zing. There's not too much noticeable noise reduction applied to images either, which is something you see a lot with lesser camera phones.
I'm old now, so the selfie camera is lost on me, but I tested it and it works well enough – I could certainly see a depressingly realistic representation of my tired face, looking back at me with the desperation of a man who's just waited three seconds for the camera mode to switch.