I just got a new Acer LCD monitor, finally getting rid of my big (but sharp) Viewsonic CRT. The User Manual is scanty, to say the least, and I can't find anywhere whether the monitor should be set for 75MHz or 60MHz. What are the pros and cons of each?

Also, I'm not sure I'm thrilled with the clarity of this monitor, and may go looking for one that's sharper. Any suggestions?