I found prismacolor double sided markers to be great! They key is get either some white photocopy paper or those specially marked pads. I tried the 'dick blick' brand markers (come on.. they are cheaper!), but those were not really that good. The tips were funky fibers.
For what I do the markers work well and are quick. I have seen people who prefer markers over anything else.. so that's a style question you need to answer for yourself.