None of the nForce4 chipsets support 1394, this is gone since the MCP-T (nForce2).
The vanilla nForce4 is only missing SATAII and ActiveArmor support compared to the Ultra. It does have Gigabit. In addition to SATAII and ActiveArmor the SLI chipset supports SLI, but Soltek is not going to use it for any board.
Macro2, it's PCI Express or PCI-E, PCI-X is a different beast.
I don't like to use the slot below the video card for cooling reasons, but only high-end cards with dual-slot cooling will actually block it.
"I'm still miffed that they used a Promise chip on my K8AN2E-GR to get SATA3 and 4 even though the chipset supports 4 SATA ports natively. I'm glad they got their act straight for this board."
For some reason a lot of companies chose to ignore the 2 SATA ports of the nForce3 that require an external PHY. In fact, MSI and DFI are the only ones that used them from the top of my head (s754 boards).