I owned the Answer Atac, Kona Velocity and the Syncros Cattleprod and I believe the Cattle Prod easily bests them all. Why?
With a stem you want stiffness for great tracking, strength that you can trust , weight savings and looks. I believe that Sycros wins on nearly all fronts all else being equal.
First, stiffness, Syncros chose aluminum as you can use more of it and therefore make larger diameter tubes which they manipulated by ovalizing at both the bar and the steerer. They also used a wider connection to the bar for better surface area and grip. My model featured an awesome brilliant hardened tool steel pinned pivot allowing bar swaps w/o sliding the bar through.
Second, strength Syncros design appeared superior by manipulating the tube which increased stiffness and limits flex which is the death nell for aluminum. Syncros even used a power "zit" or a final glob during their welding protocol which prevents the slim chance of a small fracture at the weakest weld point. They also were all heat treated.
Third, weight. Syncros did a number of nifty tricks to save weight including using a super strong alloy extension bolt. A full third the weight of common steel. Yes steel is stronger but like a chain the steel bolts into the softer alloy wedge regardless no steel is pointless. Speaking of the ally wedge Syncros went through the effort of actually maching away every last bit of weight from this unseen part, saving even more weight.
The Velocity stem was nice and smartly used a shorter quil section to save weight but its was steel and would be both heavier and more flexy than an alloy stem.
The answer stem was a beauty with nice anodizing and I believe used Easton tubing but had a standard quil design and despite the nice weld was no better than Syncros welds and simply did not have that attention to detail the seemingly obcessed folks at Syncros had.
Looks is clealy a subjective thing but I was always dran to the Syncros stem. Pretty much anything they made was the best back when they were being made by hand in Vancouver.