Is there a difference in balanced cables??

what is your system? balanced or not, can have different conclusions for different electronics (even if they offer both in terms of connectivity)...for example Ayre really does want balanced

I just compared 2 different XLR interconnects in my system - Acoustic Zen Silver Ref MkII and Audience AU24. They sound very different.

Can you describe the differences?

AU24 is a very good XLR interconnect.
But in comparison to AZ Silver Ref MkII, the AU24 appears to be a little closed in. Highs are a bit rolled off, bass is muddy and it doesn't have the attack and punch of the Silver Ref. Also, soundstage is flatter and kind of 2D with the AU24. Not as wide and not as deep of a soundstage.
I'd say that AU24 XLR compares to AZ Matrix Ref MkII, but the AU24 single-ended cable doesn't even compare to the Zen Matrix Ref II. At least in my system.
Acoustic Zen Silver Ref MkII is very resolving, detailed(but not hyper detailed), more precise imaging and soundstage is wider and deeper. Bass is deeper, tighter and more detailed than the AU24. Midrange is more open. Highs are sweet and detailed.
I have Silver Ref II from cd to pre, Matrix RefII from pre to amp, Satori ShotGun speaker cables.

Another thing....Audience powerChord is amazing. I'd take the powerChord over the AZ Tsunami Plus any day. But as far as the interconnects, just not my cup of tea. Don't get me wrong though, they are very good. It's just that the Silver Ref MkII is better...at least in my system.

Audphile 1 -- It makes sense to me that the AZ Silver Ref MkII would be much better in your system, which uses the AZ speaker cables. I recently experienced a dramatic demonstration of cabling synergy with Analysis Plus cables. Using AP Oval 12 speaker cables in my 2nd system (Sonus Faber Concertinos, PrimaLuna Prologue One amp, Audio Refinement Complete CDP, Shunyata Diamondback power cord on the front end, Atlas Eos power cord on the amp), I auditioned various RCA ICs--Audience Maestros, Atlas Navigators, and AP Copper Oval In and Solo Crystal Oval. While each IC was good, the AP ICs were best. Harmonic saturation, detail, imaging, and air all increased with the AP ICs and was dramatically better with the Solo Crystal Ovals. Playing the Huelgas Ensemble "Le Chant de Virgile," I could hear the bass enunciate and sing so well, it seemed he was in the corner of the room. It was chilling. And it made the point to me regarding synergy in a system among cables of the same make. Now, I'm very eager to try an Audience balanced IC in my main system as I've Audience Au24 speaker cables with an Audience PowerChord on my CDP. I also have Kimber Kable KCAG and an Atlas Navigator All-Cu on hand. We'll see.