its been 24 hours since i bought the Speck CandyShell grip case for the ONE M8, and its already scratched up in the back. it does not add bulk to the phone but the back looks bad now. if you are considering this case i would recommend to look for another one. Specially for the price. here is a mini video i did about it.. just saying:
http://www.youtube.com/watch?v=lYDONUvj62Q&feature=share&list=UUZrQCWWKmxfW2bOn1SuoSJA
http://www.youtube.com/watch?v=lYDONUvj62Q&feature=share&list=UUZrQCWWKmxfW2bOn1SuoSJA