No experience with those blocks, but I wouldn't go near them with a 20 foot pole. I do NOT consider any design that mixes aluminum and copper to be acceptable (Sorry Swiftech) putting brass barbs into the Al instead of the plastic that is supplied would make the problem worse since now there would be even more mismatched metal.
Otherwise the design looks like it would work, but it isn't anything special - If you believe their claims about "Incredible cooling performance! SECOND TO NONE!" I have this really nice bridge I'd like to sell you
It appears to be a basic dimpled base design that was good when it was first introduced but better designs have long since replaced it as performance king.
These guys make great fertilizer of the male bovine variety, which they have spread liberally through their add, but I wouldn't say the same for their blocks.