I am heading to Bolivia and I am not sure which city I should visit , Could you guys help me?
I was told bad things about la paz....

If you type on the net "Bolivia Travel Guide" you will get a page with all sort of information about this country. Read the tips given and decide.
This is the best you can do. The other thing you can do is cotact with readers who have been there.
Good luck and have a safe trip.