Hmm...
May I throw one more suggestion in there? I suggest the new grained calfskin Lady Dior WOC:
The reason why I suggest this is that I like this more than both the WOCs you mentioned. Of the two you mentioned, the Chanel WOC is more timeless as it is essentially a Chanel staple. The problem is that the chain strap cannot be removed, and if tucked into the bag to be used as a clutch, then it takes up room inside and leaves less room for your belongings.
The Lady Dior WOC is as timeless as a WOC can be. The strap is detachable. Comes with the elegant D I O R charms. Even better, the D rings to which the strap is attached can extend outside of the flap so the clasps of the strap will not dent the edge of the flap. The Chanel will have this problem over time, especially if the contents get heavy.