autOpsy,
I did not realize myself either, that the Madcatz pack was no good for a long time, as I had nothing to compare it to.
I just had a suspicion, when I read about the excellent picture quality of the Xbox in HD, that the quality I was getting may not be that excellent - and therefore I may have a problem (also, I got better picture quality with Svideo via the MS pack then via component from the Madcatz pack).
That is when I bought the HD pack from MS - and I immediately saw the HUGE difference in picture quality. Suddenly everything became sharp and clean - and higher resolutions ( 720p and 1080i) which were quite bad with the Madcatz pack became a marvel! (And seemingly you also see it: as the Madcatz pack should in theory be always equal or better to the composite video cable which came with your Xbox)
And as I said: the techsupport guys at Madcatz also confirmed that the Ultra AV pack is not very good (they have exchanged my first unit for another similarly bad one...)
But: if you see it just by itself - without being able to compare it, it may look ok. Also: I have a large screen ( 84") which shows differences in picture quality even more off...
And yes, the MS Advanced pack is for Svideo and the HD pack for component video. Both support 5.1 audio.
And a final comment: pretty much all games are HD compatible - only a few (old) games are not.
Miklos