I recently purchased both of these balls, the Pure Diamond and the Secret Diamond.  I laid them out the same, 70 x 4 1/4 x 35.  My thought was the Pure should compliment the Secret.  I rolled the Secret 1st and LOVED the strong, but predictable movement on the back end.  Rolled great, hit like a Mack truck.  Then I moved onto the Pure and really did not like it.  As i have seen in another post, it read at the arrows and was heavy and just blah.  So, this was disappointing.  I went home, put it on the Haus for a sec with 3k pads, then used Vise Polish.  Put it in the bag for league last night.  WOW, WHAT A DIFFERENCE.  This ball is amazing.  Conserved so much energy for the back ends and killed the pocket.  Now, the ball is still a big hooking ball, but it gets down lane.  I normally dont like to start left of 25 on fresh THS, but i was determined to see this through.  Ball was amazingly clean.  I finally had to ball down the 3rd game, but was very pleased the 1st 2 games.  I will post another review of the Secret when i bowl on oil.