The UIPickerView class implements objects, called picker views, that use a spinning-wheel or slot-machine metaphor to show one or more sets of values
UITableView is a class used for displaying and editing lists of information on iOS
"The uipickerview is nothing more than a uiview with one or more uitableview and background and selector views"
from question "Customize UIPickerView's Skin with images"
"Uitableview is much more customizable than uipickerview"
from question "Is it good to show a UIPickerView with only small data size?"