As highfigh posted the audioholics article. If you have the option, use xlr when you can. People are going to debate whether or not they give you a lower noise floor or not. Honestly it's probably dependent on the equipment being used. Personally i will use them whenever possible, it cuts down the possibility on any interference to
almost zero.
The connections are great (secure) cable is usually heavy duty, and if for some reason you need to repair, it's a simple process. No need to throw out the cable like you would with an unbalanced rca cable.
For value to performance ratio, i like Audioblast xlr cables. Great build quality and great company to deal with.
They pretty much have every option available, if you cant find what you need. They will custom make them at no extra charge ( just will take about a week to get ).
Amazon.com : audioblast xlr cables
A few years back when they first started out, i bought some cables to try. They later asked my opinion on them, they then sent me a bunch of cables from Mogami, Canare and a few other companies to compare to their cables. Must have been a few hundred dollars worth of cables, i was shocked they would do that. It did seem to prove that the Audioblast cables had a better build quality.
In short, All i can really say is i have had cables from many different companies, priced higher and lower. The Audioblast to me are a better quality and are not over priced.