The difference between the Spir@l and the Gemini Blocks isn't huge. The Spir@l was designed for the hardcore overclocker. It is one SOLID, MASSIVE block of copper. It is a work of art in my mind.
The Gemini block is puny compared to the Spir@l. But don't let this throw you off it can dissipate the heat produced by AMD cpus + Peltiers. I myself have installed the High Flow block w/a 172 watt pelt. I don't have it up anymore, it was for testing only. It was running REALLY cool =). I'll have the full rig up soon, but i need to work on condensation issues first. The low volume Gemini is extremely small. when most ppl see it they are liek WTF is this..cuz its' SMALL, but it performs very well. Like in Hoot's article he's surprised by the size, and the performance.
These blocks go against most overclockers mentatlity that MORE copper = Better performance. Teh bigger the block the bettter the performance is what most ppl think, but it's not always true. If u look at Alpha heatsinks, They don't use all copper, yet every well most ppl beleive that all copper naturally means better, but design matters a lot more in most cases.
I'm not trying to say one is better than the other, both were meant for different reasons, and you can't go wrong with either. The Maze 3, is still un-proven, i would wait a bit too see users results before i dive it. The Maze2 was a great block and one can only expect the same amount of workmanship and quality in the Maze3.
-JokerF15