If you are talking just keyboard, then it works fine. I can't get myself to do mouse and keyboard usually so I just keyboard for me when I play on PC, but I still prefer the ps3 with controller any day. Then again I am on WHM so I don't have to worry about fairy positioning.

That said, keyboard takes some getting used to over controller at first, but just run the lower dungeons a few times to get the basics down. As a best approach to practice I would say easy test maybe do Haltali to get the general mechanics down since even if you screw up it is no big deal, then Toto Rak, since it is easy, but does have a little bit of movement in the last boss. Then if you think you have the basics down, try for Qarn. A lot more movement and positioning, and sudden burts of damage to heal, so a good test for your ability to keep up moving and healing at the same time.

I haven't touched Titan on keyboard, the very idea freaks me out. Controller any day there.