The Pocket Lens is amazing since it fits every smartphone. It can be used on both the back and front facing camera. It can even work with your MacBook or laptop.
Since the Pocket Lens is small and sturdy it fits in your pocket so you can take it anywhere. No searching around, just snap it on your phone even over your case and start shooting.
It only has three simple parts. While it is easy to put together it will usually already be assembled so no searching around to add or remove a lens, just leave the landscape on and if you have a great macro pic, unscrew the landscape and you're ready to go.