Like I said... if you see a subjective difference, it was worth it to you. If you still have the old cable, I would be interested if you could check test patterns as I said earlier so we would have an idea of what the changes you're seeing actually are based on known references. You can download a free disc of patterns here that will play in any Blu-ray player or your PS3. You don't need equipment to do this test... Only your eyes. And if you haven't calibrated your set, this will help you anyway.
I used to have a cheap cable (I believe that was packed in with my old Panasonic S97) that was HDMI 1.1, and it wouldn't pass 1080p at all. So I'm not saying that I haven't seen "a difference", because I did - one cable didn't work, the other one did. The question I'm positing is if, in a system wherein there should not be a difference, there is a difference, how does that difference exhibit itself against known references? If you're game to try it, it would be interesting. For that matter, if you don't want to do it and you still have the cable, I'll pay shipping for you to send it my way and I'll swap it into my system that is calibrated as close to reference as possible to see if it creates visible issues. Could make for a fun exercise!