Thanks for all the insights here.
After shooting more than 50 music videos with my NEX5N, some idiot broke into our house yesterday while I was having a shower and stole it, along with my iPad 2. Thankfully the camera only had my old Nikon f2.8 28mm lens on it. They left behind the charger with spare battery, Lens Turbo and other lenses.
So I've just decided to get this A6000. To be honest, I never really had a problem with the image quality I was getting from the NEX5N. A bit of aliasing here and there, some loss of detail if I used noise reduction on low light shots, etc. But I never had an EVF, the thing always overheated, the LCD had a big splotch mark in the centre as I'd never bought a screen protector for it, it didn't have zebras, and I never had a kit lens which would have been good for travelling. So the A6000 with a kit lens seems like the perfect replacement. And affordable too, as money I've made from a couple of videos this past week will easily cover the cost.
From reading this thread though, I'll agree some of the Panasonics may have better image quality. The Nikon 5300 too. Although I've never owned a DSLR, and never will. I really need that focus peaking. With the NEX5N, as long as I could see a red spot in someone's eyes, I knew my focus was good. And with the Lens Turbo, I can get that full frame look if I need it. Which wouldn't be possible with any m43 camera, or even the 5300.
One other thing I do is always shoot in 50P, normally with a 1/100 shutter. Unless it's something on green screen. For music videos, being able to slow down a clip really easily I find to be a lot more important than a few possible artifacts the intended audience will never see. That slow mo can add emotion to a clip that you wouldn't get at normal speed. And for that reason, none of the affordable Blackmagic cameras are an option for me either. Or any affordable 4K camera. Better to wait until they can all do 4K 50P and without the rolling shutter. And to improve image quality, I use Neat Video followed by Boris BCC film grain.
Anyway, apologies for the rant, but I guess my point here is to not be too concerned about image quality, artifacts and all that, but to go for whatever camera has the most features that are important to you. In my case those are compatibility with existing lenses (including my Lens Turbo), portability, focus peaking, a file format that's simple to edit (AVCHD files work great in Sony Vegas!), good low light performance, and 50P. In which case, this A6000 appears to be my best option. I'm hoping to pick one up later today. After I enquire about getting some security screens for our windows :)