I am ashamed to say, I have the magnitude, and it's a lovely piece of kit, but it is not worth the price for the very small gain in performance.
The Magnitude, and Optimus Cpu blocks represent the best of the best in performance and quality, but unless you're at the point where 1-3 degrees matters, you're best off saving your money and getting any number of blocks.
The Magnitude replaced and Alphacool block I have on a 5Ghz All core 10900k. No real difference in performance for me. If you like the look of the EK blocks, I'd go for the Velocity and save £100