I agree. I had a fresh string job and let the string bed settle in for 2 hours or so. Then I would play a set or two with amazing spin and feel but if I played the match the next day, the balls would just feel like they were spraying everywhere. I had to slow down my swing speed instead of taking aggressive cuts with it because I was afraid of where it would end up. Also while stringing it, it was sharp and if you are the type who hits tennis rackets on your knees occasionally... DONT or you will cut yourself.I've used UC about 6 or 8 times. Always strung on a constant pull and I've tried both no-pre and pre-stretched. Pre-stretched made it last a little longer but not a lot. I use a PS85 and strung at about 45lbs which is similar to stringing at about 53lbs on a 95 sq in frame or thereabouts.
A key issue with the characteristics of this sort of string is it really only shows it's best side with decent swing speeds. But if you have decent swing speed you'll also loosen the strings quicker too and these loosen particularly quickly. If you want generally better life-span then try Blue Rock. If you want much better life span but can handle slightly less spin then Black 5 Edge is a good option to try.