I've been studying/practicing portrait in oil this last year. I really enjoy how oil blends and retains a beautiful texture. Acrylics can too, but because oil doesn't dry so fast, you can work it until you're happy with the results.
This is my friend Priscilla. Painted from a photo taken at a gala when we were all dressed up. I probably should have worked it just a little longer to look most like her.
These two are from old photos provided in the class I took at the Art Student's League. Again, they don't look exactly like the photos, so I need to keep working on that, but I really started to experiment with glazing and wet-on-wet techniques.