OIL VS. WATER MIXABLE OIL

I've wondered about the differences (if any) between WMO V OIL paints so did block study.  I think oils may be richer in intensity and surprisingly dry to the touch quicker.  WMO have a consistency I like especially Holbein Duo.  The study was in lighter colors but oil yellows seem to come thru as richer. What do you think? The one above WMO and below O