Is the D800 better value than the D600?

I ask because I am considering either of these two cameras. Whichever one I choose will be my main camera for years to come. The price difference is around £550 GBP at the moment. I am not a professional photographer but I am very keen. I may turn pro if my photography continues to improve like it has over the past year or so. I have been an avid photographer now for over 30 years. My last fully pro camera was a D2x before downsizing to a more prosumer D300.

I take all kinds of pictures from wildlife/birds, architechture, landscapes & more recently astrophotgraphy.

Do these following features, to name a few warrant the extra £550?

​D800 ​Advantages

50% Higher MP of course

Full metal body

Bigger Viewfinder

Better weather sealing

Dedicated AF-On button

Higher flash sync speed & PC sync socket

USB 3

Against these advantages for the D600

​D600 Advantages

Much lighter

Slightly better against noise at high ISO's

WU-1b compatible

Faster frame rate at full res 5.5 fps versus 4 fps

Cheaper battery grip

Twin SD card slots

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