What's better than HT Platinum Digital cable?


If you have lived with the HT Platinum digital interconnect for an extended period (3+ months) of time and then upgraded, what did you upgrade to? And what improvements if any occured? Where you satisfied with the upgrade?

I'm particulary interested in selecting a 1m S/PDIF in the $300 to $350 range. Here's the short list I composed as of today:

AZ MC2 $298
Stealth Varidig $300
Purenote Epsilon $350
ed_f
Texas25,

Haven't read much here and at the asylum to convince me that $400 Magic One is a really leap in performance over the HT Platinum.

I recently replaced a HT Truthlink with a PureNote Epsilon analogue interconnect. I guess I am moving away from the big players in favor of the more niche web-direct vendors in an effort to seek out more value and performance for the dollar.
I'm curious why anyone would spend several hundred dollars on a "high quality digital cable". As an electrical engineer I question the merits here. The beauty of a digital interface is, like your computer, that the signals are logic "1" or "0", not logic "1.00372" or "0.0345". Precision connections are not necessary here. Noise, unless it is extremely bad, is not an issue. Getting back to your computer, the internet (landline, sat or DSL) enables exact (read: no degredation) digital copies to be transferred over less-than-precision cables (e.g. phone wire). Because I don't consider myself to "all knowing" and am always looking to learn, please enlightnen me as to how an expensive cable can improve upon this simple relatively low-speed interface.
Hockey: Yes it is just 1 and 0 logic, however if the signal quality is poor because of a poor quality cable, the D/A decoder chip in your DAC will have to work harder to find the correct signal and decode it. This will affect the sound. The poor cable can also affect things like the timing and pace of the signal (and hence the music), even though all the data will arrive. These things are not an issue sending computer data, unless you get upset that your computer data arrives a fraction of a second later than you expect.

It is the same as high speed data (faster than DSL) needs a better quality cable than standard telephone cable. I live in a rural area and have never gotten a faster connection than 43.8kps on my 56k modem. I usually average around 38.6K. The quality of the phone lines is just too old here. I can get digital cable TV here. However, they had to install better quality cable in the ground to get it to work. The old cable TV lines could not handle the digital TV signal well enough to actually see the improvement.

I am actually on your side in part. While I believe a good digital cable matters, I doubt is it as crucial as an analog audio signal.