I was researching on popup/modal views to use, and finally decided on RNBlurModalView, which has a nicer blurred background effect.
Nonetheless, others are good depending on your use.
Here are 7 custom popup views for iOS:
UAModalPanel: Simple dismissiable popup
RNBlurModalView: With a blurred background
MJPopupViewController: With different transition effects
ALPopupView: Facebook-like popup ($19)
FPPopover: iPad-like popovers for iPhone
WEPopover: Another iPad-like popover
CMPopTipView: Bubble Tooltip
PS: I created JDToaster 2 years ago, which unfortunately I didn’t update..
WCAlertView: UIALertView with blocks
UIAlertView and UIActionSheet with blocks
Cocoacontrols - for more popups!