I have been climbing on Sterling Ropes for the last 12 years and was even sponsored by Sterling for a period of time. Needless to say, I stocked up on product! Way back in the early days of my climbing career, I haphazardly bought ropes that were either on sale or ropes that simply came in interesting colors. Through that experience, though, I actually learned which rope companies I preferred, and I also learned about the value of paying for a high quality rope. You get more out of a Sterling Rope as they can last multiple seasons when properly cared for. Some ropes just do not perform well, get cable-like, are too heavy, or will not stand up to the rigor of projecting a route. I am now very particular about the type of ropes that I purchase, and put forth a lot of effort to keep my ropes in good condition.
My initial purchasing assessment of a rope includes the diameter and length of the rope, and I also opt for dry treated ropes. The fall factor, elongation and stretch of the rope, and overall materials used for construction are also important aspects to know about your rope purchase. The UIAA is an accredited and independent third party entity that is used internationally by rope and gear companies to certify safety standards. Color and duo patterns are really secondary concerns for me but are an added bonus. My go-to Sterling Rope has been the 70 meter, dry treated, 9.4 millimeter Fusion Ion. Having a light-weight rope that can also withstand projecting days is hugely desirable. We buy 70 meter ropes, so that when we need to, we can trim and singe the ends of the rope and still maintain a safe length of about 60 meters; a great length to use at Rumney.
I remember this one occasion when I was getting ready to attempt to redpoint and another climber asked me to use their rope. She was planning on going next and wanted a top rope set up so she could safely work the moves. I was in the middle of mentally preparing myself by rehearsing beta, so I politely said "Sorry, no thanks. I need to use my own trusty rope!" In instances like that it would be unsafe to climb on a strange rope. Plus, clipping would feel different, and the rope would likely have felt heavier than my 9.4.
It is clear that climbing ropes are a lifeline for climbers, and they are also an expensive part of the gear closet. The Fusion Ion retails for about $278, but is totally worth it. Just remember that going in straight on your gear when hanging will save the rope and you some $$.