Which is the lesser of all evils?

So, I'm due for a company phone "upgrade". Yes, I realize that all these phones are an overpriced POS (this is NZ, everything is extremely expensive). Now, I can't stand any Android that isn't stock Android, or close to it (I love Nexus devices and Cyanogenmod), but unfortunately I'll be stuck with crappy 4 year old hardware and an extremely bloated OS. Those Windows phones look tempting, but only have 512MB RAM so I'll rule that out. If it were up to me I'd ask for a OnePlus One, Nexus 6, or 2014 Moto X but the boss won't fork out for those!

Unfortunately I can't root and flash CM since it's a company phone. So which phone out of those in that screenshot is least likely to drive me crazy?

In this order, Lumia 635 will get Windows Phone 10 soon. Preview was just released for it.

1. Lumia 635
2. Xperia E3
3. Galaxy Core

We have four android Xperia phones, three Samsungs , one ZTE and two Lumia.
ugh the frustration the androids sometimes can be.

Running a Lumia with WP feels like a breeze and I prefer that,
much easier to use and the amount of apps is sufficient nowadays.

For 512M RAM has not been a issue for me on WP.
Check out the newer Lumias (535, 735, 830)that have 1GB RAM if that is needed.

+1 for the Lumina 635. I don't have any experience with Windows phones, but I'd rather have the Lumina than any of the android options up there, especially if it's getting the Windows 10 upgrade. Second place would be the Xperia E3 for me too. That said, they are both very much the best of a bad bunch.

Can you buy your own? For instance, get a used 2013 MotoX for a good price and use it on your carrier? That would probably be better than any of those options.

Sony Xperia. honestly, it is considered one of the best build qualities and it has some top notch specs. It would be stupid to go with most of those other phones.