XLR or single ended cables and why?

Few audio equipments reviewers swear by their reputation if there is any that XLR connections improve quality of the sound sonically. Some stated there is none. Can someone scientifically help me to make a wise decision to choose between XLR and singled-ended cables?
In my mind, I think of it this way. First: Do you need to deal with very long runs (say greater than 30 feet, and yes, I did just pull that number out of the air ;) between source and pre or between pre and amp? If so, stick with XLR. If not, go with whatever is attached to the equipment you think sounds the best. The only place XLR will hurt is your wallet when you factor in the premium most makers charge for having it and the only place it will help is on extremely long runs. Make your decision based on what equipment sounds best to you, not on what type of interconnect it uses. Hope that helps!
Depends if the components are designed as truely balanced or not. For instance, don't by BAT gear and run it single ended. Your not getting the sound you paid for.

I would reccomend a quick forum search on this subject.

I have read some fabulous threads here on this subject, which included the participation of the designers of some of Audiogon's most well respected gear!

Since in your post you do not state whether your gear is balanced by design, there is no simple answer.

Originally almost exclusively reserved for pro-audio use, balanced components are designed to operate in unpredictable professional working environments They offer maximal S/N (signal to noise ratios), and standardized connectivity. Today's well-designed balanced high-end equipment, when connected with balanced IC's, offers the benefits of lower noise floor and better radio frequency (RF) rejection.

On the other hand, well-designed unbalanced equipment offers sonic (and sometimes lower price) benefits which make simpler circuit topologies popular. These designs can, however, be more prone to RF noise, which has become (with Cell phone, microwave, computer, and WiFi) an increasing feature of the home environment.

Hope this helps,

If you don't find your answers by reading previous threads, please let us know more about the boxes you are connecting up.

For the music,