I think they got a hard time. The FX5800 and the Fx5800 Ultra were noisy beasts, but they FLEW in DirectX 8 and openGL games. The FX5600 Ultra was on a par with a GF4Ti 4600 in DX8, with the added bonus of being a cheap mid range card and it could stagger through 3Dmark 2003 half respectfully. The 5200 was a bad joke as far as games went, but it was a low end card ... ok I can't defend it the 5200 was SHITE.
Of course, in the end the 5950 Ultra later revisions were amazing - fastest of it's generation but way too late in arrival. What killed the FX series (apart from the 5200) was ATI's cards. Specifically the early 9500 and the 9700 pro. They punished nvidia without mercy. But let's be honest - nvidia had it pretty good up until then from the GF2 ultra, GF3 and GF4 Ti series with ATI limping along crying all the time.
Having said all that, I have a 5950Ultra and wouldn't swap it for 9800XT even if you threw in a bag of Skittles, 2 conkers and a KitKat.
I just avoid directX 9 games like the plague.