Conclusion
Both Silkypix and ACR are very good tools. I found that I was able to get comparable results from both of them, especially when you use ACR in conjunction with Photoshop (which of course is how it was designed to be used). Is Silkypix better than ACR? Well, it does have some great features that are missing from ACR. For example, its addition of some powerful noise reduction and sharpening tools to the raw workflow helped me envision the final image much more quickly than ACR. On some challenging images, this immediacy can be very helpful. But comparing the two has also increased my respect for what ACR is capable of, especially when combined with Photoshop's Smart Sharpen and Noise Ninja. And since I greatly prefer Adobe's workflow, it will continue to be my standard tool.
But what I found most interesting was how Silkypix forced me to look at my raw processing techniques differently. With it quirky interface and oddly written labels, Silkypix forced me to slow down and pay attention to what I was doing. I began to realize I had been getting lazy with ACR, relying on its presets and default workflow a little too much. Many times when I didn't like ACR's results, it was more due to my laziness than to any limitation of the program.
By trying to achieve similar results from these two very different tools, I learned quite a lot about what I could achieve in my raw images. Having a different set of tools to approach the same problem gave me a whole different set of assumptions about what was possible. This alone helped me unlock more potential from my photographs.
ACR will continue to be my primary raw converstion program, but I may include Silkypix as an additional aide, alongside Kodak's raw converter PhotoDesk. Then, when I am working on a difficult image, or I am just plain getting sloppy with my work, I can use these other tools to shake up my assumptions. I have found that having different tools for the same job forces you to make the decision about the results you want, instead of just relying on the tool to do it automatically for you.

Silkypix (left) vs ACR + Photoshop (right)