Generally I prefer a "built-by-ATi" card to any third party card - my 9700pro is a "built-by" - I think they generally have the least problems.
that being said - I didn't know ATi produced their own 9100's - I've only ever seen 3rd party boards - & their wesite doesn't list it either. My supplier is an ATi partner as well & he doesn't know anything about them.
Call these guys up and ask them what the clocks are - I wouldn't buy any Radeon with out finding out exactly what the clocks are first. ATi has been known to produce OEM cards with lower clocks in the past