I have both. IMO the Lock is much, much better. The Lock has better carry, and a much better roll vs the Sinister. I have changed the cover on my Sinister a few times and still don't get the reaction as I do with my Lock. I did make one cover change to the Lock, I went from oob to 2k with polish.Since then, it has been the best rolling ball I have had in a while ( at least for me). The Sinister, maybe if I had a different layout on it, would it roll and finish better? I don't know. All I can say is the Lock is in my bag, and first ball out. My Sinister is in my basement and its up for sale.