Is shielding cables that important?

JPS Labs Ultraconductor has solid core conductors and no shielding. Because of this, is it subject to interference and hum? Nevetheless, even with these caveats, the sound seems to be terrific. Is shielding that important?
Your question is much like asking whether automotive seat belts are important. If you need them, you had better have them. Many people live in areas where RF and EMI interference is not strong enough to require shielding. Provided other equipment in the system is not an issue, unshielded cables often sound better. Unfortunately, until you experiment, there is no way of knowing in advance. Your post indicates that you are extremely happy with your present cable, so I would leave it as is, unless you develop a problem.
Years ago I had this Kimber,KAGC /I thing those are the letters/ anyway,it's the braided no shielded cable.I never had a problem. Albert;when you're driving those soundlabs;you should have those seat belts on;air bags/ optional.
Van Den Hul makes cables both ways. "The First" cables are unshielded. "The Second" cables are basically the same construction but shielded. "The First" performs better in most opinions, so the shielding must have an effect on the sound.
I agree with Sugarbrie about the VDH cables, that was my observation as well. Same is true with the Kimber PBJ vs. their KC-1. Most reviewers seem to feel that the PBJ sounds better. If what you've got works well, I wouldn't worry about it at this point.
No need really to give my two cents worth, except for my experience with various XLO cables as well as the VDH's, mentioned above. I always preferred the sound of the unshielded cables, whenever I could safely use them in my system. ( More openess, more dynamics, better "bloom", better highs with the unshielded XLO's using mostly tubed gear )
Shielding isn't actually effective at blocking all frequencies anyway. If you are really concerned about high frequency noise, a combination of braiding and sheilding probably the way to go.

The theory is that the cables that are unsheilded sound better because they allow the signal to generate a fuller magnetic field around (outside of) the cable. The sheilding can retard the fields of the actual signal, just like it does for external noise.

I use sheilded cables for digital and video. Unsheilded for audio.
Sorry the EE in me can't let this one go. :-) The magnetic permeability of Copper, of which 99.9% of all shielding is made, is the exactly the same as air, which is one. Copper does not impede magnetic fields. When you add a shield to a cable you increase the capacitance of the cable. The shield acts as a ground plane at a relatively small distance from a current carrying plane separated by a dielectric, hence a capacitor. However in a well executed design, the capacitance introduced by shielding is usually very small. This could be the cause an audible difference, or it could be the cable is doing its job properly and it is letting you hear more "grunge" in the original signal. - Cheers, Dan
Dan, at last! An engineer that speaks to the reality of design with accuracy and understanding.