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!
I have the so black chevron reissue (from 18S) and have had zero issues with the hardware-still looks perfect! However, if they had had ruthenium hardware in chevron at the time I purchased my bag, I probably would have gone for that. I much prefer chevron over the classic quilting and I think the combination of chevron with RHW is stunning! Good luck with your purchase; you can't go wrong either way!
I have the 226 size in black RHW and the mini so black reissue. I have to say as much as I love the so black, the RHW is just more suitable for everyday! And I don’t really worry about potential chipping.