Taking the plunge on an A7 Camera

[sbreingan]

I've been enjoying my NEX-5N for the last few years, and because of a significant birthday this week I'm looking to take the plunge to Full Frame. 

It's between the A7ii and the A7s. There seems to be a pretty good deal on Amazon at the moment where the A7S is down to £1600 compared to £1400 for the A7ii. Especially considering, as I understand, it also comes with an extra battery and charger.

I want to get into video but I'm really just starting out, so would probably use it 70/30 for stills to video. 

Pros for the A7S - better ISO, silent shutter, 120 fps, lighter body, better focus in low light
Pros for the A7ii - IBIS, high resolution, slightly cheaper, better focus in normal light

I'm an enthusiast, not a professional, and don't tend to print too much. I tend to PP in an analogue style using VSCO. 
I've heard people say that the A7S renders differently because of it's lower MP count and it's feels more like medium format (which I dig). Does anyone who has owned/used both feel like there is a noticeable difference between the files at lower ISOs apart from resolution?

I mainly shoot primes; I have my eye on the 55/1.8; I know there are many factors in what makes a good lens but is it wasted money to pay that premium and only ever use it with a 12MP sensor?

I'm not likely to buy another camera anytime soon, so I'm after one camera to take everywhere and cover any situation. On paper the A7ii seems the better choice but I'm drawn to the A7S.  Any advice is greatly appreciated!

[Michael_j]

Unless you are a video specialist I should go for the A7Mk2, it's an excellent all rounder and the video standard is extremely acceptable.

[MichaelComeau]

If you want the medium format feel... go for medium format. Even 645 film is vastly different from a 35mm-based system.

 

I love my A7II, but if money was no object, I'd take the A7S for the silent shutter.

 

The 55mm f/1.8 is amazing (my review is here) and I don't think you're losing anything with a 12MP camera unless you're printing extremely large. 12MP is more than enough if your stuff just ends up on the web.

[sbreingan]

Brilliant review, thanks so much. I am so tried of reading camera and lens reviews that just put endless graphs and test patterns.
It sounds like the kit lens is worth the money also.