Lorraine, oils fetch more. 97 percent of paintings sold (dollar amount) in galleries are oils, excepting the moderns which use house paint and acrylics. To my students who want to use water-based paint I suggest Holbein's Duo brand (water-solubles). They never go back to acrylics.
Oils are easier to work and the effects you can get far exceed the others. Watercolors I like, but the buyers never pay the same prices per inch.