Same exact question I had some time ago! was hesitating between both, I was really convinced I would prefer the so black in chevron. When I tried both at the boutique, I found the ruthenium to be more casual therefore more adapted to my style and to everyday wear.
I had issues with the so black hardware on the coco handle after only one week wear -I used it every day for a week- (luckily Chanel changed the entire bag for me) but since that episode now I am scared that it will chip again and I don't use it.
Bottom line, the ruthenium was the best option! and I do use my reissue a LOT!