ive bought 3 of them and two of them have slowed down considerably, one of them is near unuseable condition after using silicone lube?(lunar and martian) i cleaned it out 10 times and is still sluggish like no tommorow? i learned my lesson and only used stardust on the other and its gotten a bit slower over time but not remotely to the degree the other did? im guessing the plastic the cube is made out of does not like silicone lube it binds to the plastic and you cant clean it out leaving a super super gummy slow feel to the point it takes serious effort to turn? its very fast out of the box and if it stayed like that it would be a easy 5 stars no doubt, for the price its fine all and all though as long as you baby it with the lube and clean it right