I need to go back and check the length of my cable, because I think I may have misspoken. At the time I bought the cable, they were claiming it would support 1440p, but their web site only claims to support 1440p on 5m cables now.
Anyway, in answer to your question, I am watching Blu-rays at 1080p. It is a pretty good distance for an HDMI cable, but as you said, I'm not getting any "sparklies" in the picture. The picture is pure. I'm not sure that swapping with the DVR would do me much good since the DVR is running to the TV on another long HDMI cable (the DVR sits above the PS3). But switching the cables would bypass the HDMI switcher and the short HDMI cable running to the switcher. I'll have to give that a shot. I just wasn't sure if it was a PS3 issue or something specific to my set-up.