Question RE: mpeg2

[BTBuck1]

I see a bunch of talk about how mpeg2 is a poor codec etc. on this and other forums, While i'm not that well versed on the differances i understand that mpeg2 isn't as well compressed. My questions are the following: Isn't mpeg2 what they use for HD Cable? if so...is the mpeg2 codec the reason HD cable gets all blocky during say a fireworks scene or an explosion. If those are attributed to mpeg2 than that sucks that sony uses that. If it's a bandwidth issue than i have no problem with mpeg2 as i see a great HD picture on my cable aside from the occasional blockiness on action. So if this is mpeg 2 doing this than i'd like vc-1 otherwise as long as sony gets 50gb out soon so i can get added content and more audio options I'm okay with an "outdated codec".