I am relatively new to cablevision high def (a couple of months), so I can't compare it to a year ago. I am in Westchester, using the current DVR box (can't remember the number and at work). I also watch CV HD at my dad's house, who has the non-DVR box. I'll try to get the numbers. I have plasma (Pio 5070) he has an LCD (Sony 40 V-2500).
The new Voom channels, and most of the others look pretty good to excellent to my eyes, but more so at my house than at my dad's (also in Westchester). At his house, I definitely notice more pixelation/macroblocking (I believe, I am not a pro on what the the terms refer to, let's just say lower image quality). To be honest, I was beginning to wonder if the difference was due to Plasma v LCD: I thought the feed was the feed -- I didn't realize that the box could contribute to PQ if it was in "pass through" mode (i.e., not interfering/processing by upscaling/de-interlacing the signal). There is, however, definitely a difference from my house to his (and I don't mean in color/brightness/sharpness, but the presence of visual signal artifacts). I really should check out my brother's house, because he has an LCD with the same DVR box that I have.
As I have mentioned previously, I was ready to pull the trigger on FIOS, now I am wait-and-see. CV appears to be making an effort to broaden and improve service. They haven't turned me into a fan, but they have bought themselves breathing space, especially with Verizon dragging its toes on Fios TV availability in my region.
Eventually (probably this fall) I'll be switching to cable-card on Tivo Series 3 box, which will be an interesting comparison.