Acrylics dry way too fast for my purposes. I find that I have to add a retarder in order to work with acrylics for the particular kind of word I'm doing, otherwise they dry long before I'm ready for them to be dry. I love oils for that reason... you can work and rework them for a long time. But I need to be able to put a new layer on without having to wait 6 to 12 hours between layers, so I've taken the plunge and I'm learning how to paint using acrylics. It's a whole different way of relating to the paint and to the process, I find. But the retarder helps a lot. That, plus adding a lot of glazing medium and water.