They're flaky because of early ASUS A8R32-MVP BIOS which most has been fixed now with the latest BIOS(see Anandtech). Being only 3weeks old so far the DFI LANParty UT CFX3200 has had no major problems with its initial BIOS. Newer BIOS for both boards are continuing being released to further improve overclocking and stretching its lead over nForce4 series.
Some benchmarks prove it, ATI cards run faster on NF4 setups than with ATI's own chipsets!
Only existed noticiby on A8R32-MVP which has been fixed by lastest BIOS as shown by Anandtech.
The ATi Xpress3200 chipset itself does not have any technical issues.