Do you have a link to the offer esuorez? I would like to look at these HDDs. I wouldn't worry about below par goods though, as Seagate are a HUGE international corporation and would suffer greatly if they started shipping out naff HDDs, especially as Maxtor are very close behind in the HDD stakes.
I would say that Seagate may well be shipping out their smaller HDDs to make way for the new 500GB discs they have, plus they not long ago shipped the first ever PC to come with a 400GB HDD as standard so 250GB and 300GB HDDs will be surplus to their needs. But they will still come with Seagates warranty though