If you can afford to get both would be best!
Otherwise, lady dior I guess? As for me I owned two coco handle in small (a size aft mini). One in black matte ghw & pink rhw. Also a lady Dior medium in pearlised pink (lotus).
I bought my lady Dior on September 2016 from MBS, Singapore and I only carried it out once to the mall during Christmas. The lady Dior is really classy & makes you feel "kinda princessy" though I was just wearing a skirt & an offshoulder top.
Later in Dec 2016 & April 2017, I gotten two coco handles from personal shoppers.
I must say that I would prefer using my coco handles over lady Dior as it's style seems sturdy, also caviar & easy for me to move around.
Aside, it is versatile. If you like it more dressy, take off the shoulder strap & put on a twilly. If you prefer to be more on a casual note, just sling it on your shoulder or crossbody.
Meanwhile, my lady Dior is really to adore. Like I will take it out just to adore & chance upon when to carry it again. Maybe this Christmas so make it twice in two years. It is really dreamy to owned a lady Dior.
I don't use my bags much, I paid a price for it & expect perfections. It is like an art of craftsmanship to me.
Anyways, can't go wrong with either.