SCRABBLE_CZAR  Quinn's random generator is as random as it can be. It uses a popular equation which is referenced in the simonhaertel.de forum, and is very well done.

You may get multiples of the same pieces at times, but that is the product of the game being more random, not less random. If you play a long game, it will average out, and the piece distribution can be found by using the console. The Help section on the quinn site and in the app itself detail just how to check the distribution of pieces.

Quinn is awesome!! The best game of its kind anywhere for any platform!   
(Version 3.5.3)