3.3ns on 9800np are in fact 2.8ns chips labeled as 3.3ns with different timings in the bios, a flash to 9800pro bios will "get them back" to 2.8ns specs (~)
As for quality, well check out
This baby ... that's quality... quality can be seen as "where the hardware can do more, for how long, what are the components (good ocable graphic memory, a good HS, as VIAN said, good bundle even since some ppl look for what goodies come bundeled (games, softs, cables, adapters, readable manuals) all that make these few $ more or less in a buy make sense.