There are good points with Sharia, Moslems frequently point out that Widows and orphans should be looed after for example. Unfortunately there are many areas where decent civilized people will disagree with Islamic rules.
Problems with Muslim Sharia Law
Sharia allows slavery. Mohammed himself owned 40 unfortunate slaves. Slaves are helpless before their masters, can be bought and sold and masters can have sex with female slaves whenever they want to.
For more about abuses suffered by slaves under Islam see