Canon 6D vs Nikon D600 (for travel use)

Hi,

I plan to buy the camera, but I'm a bit unsure if its a good idea since many of you see so many negative points...

I like shooting landscapes, timelaps and stars and I travel fairly often with my camera.

Currently, I'm a Nikon D90 User, bought the GPS GP-1 and have 3 lenses. After 4 years, my remote shutter plug is broken (repair would be about 300$), my GPS is broken (the guidance rail for the hot shoe are broken).

One reason I plan to buy Canon is because one can do exposore ramps (with Nikon you can't do that, because theire minimal step width is 1/3 stops, which leads to flickr, at least with my D90). Beside that, I (still) think Canon is more inovative when it is about new features and new lenses (e.g. they try DO lenses).

The advantage of Nikon would be that I can reuse my lenses...

The advantage of the 6D would be the built-in GPS, since I plan to buy one anyway. I don't have to buy one extra (price advantage) and also don't have to care about it, since it's built-in). The camera is a bit lighter.

The advantage of the D600 would be the better overall specs and the built-in Flash, but most of my shootings don't need a flash, so it's a minor advantage.

So I'm in between, what would you recommend...? I'm prepared to switch, since my lenses are fairly cheep (except of one). I plan to buy faster lenses anyway. But once I bought some expensive, fast lenses, it will be hard to switch... So for me, in point of switch, it's a "now or never"!

Regards,
Stefan