Im no expert, but word around the interwebs is unless the adapter uses TI components, it's never a sure deal if it'll be compatible or not. Also, some are of the opinion that expresscard adapters are less reliable than the onboard chipset but I don't know the reason for this. Wala pa kasi masyadong gumagamit so hindi pa talaga na-test. E sa PCI naman, a lot of people recommend PCI soundcards. The expresscard, being a newer technology, I would think should offer similar stability. But then again, that differs from computer to computer.
Dun naman sa belkin, that sounds like a good deal actually, kung nagdecide ka na na ittry mo sya. At least may pangalan yung brand. Nung nagtanong ako before, 2k+ yung expresscard adapter tapos di ko pa naaalala yng brand.
And the belkin allows FW800 streaming? I can't verify that myself... I've never used FW800, 400 lang.