According to the reviews and talk online, the PC version is the superior version by a significant margin. Some of the advantages of the PC version are better graphics (obviously), a better UI, and the ability to put the camera into isometric view similar to the old infinity engine games (i.e. Baldur's Gate et. al.). For control, on PC you have a standard spell bar and can click the ground to move, but on console you have a radial menu for your skills and have to move using standard 3rd person controls. This means that in combat, on the PC, you can queue up all parties members exactly where you want them to go without controlling them manually.
But the biggest advantage to the PC version, in my opinion, is the toolset that Bioware just released to create user campaigns that you can download for free. They talked about porting some of the best ones to PS3, but on PC you will have access to everything.