Finally got my board today (darn weekend made it take longer!)....and here are initial assessments:
First, I have 3 boards I am using for HTPC / Media Server duties including the Asus P5Q-EM (G45), M3N78-VM (nVidia 8200), and of course our Asus P5n7A-VM (nVidia 9300):

A look at the layout (and the actual nVidia MCP7A w/o heatsink on):

There's plenty of space for a nice big HSF (like my Ninja Rev. A), well laid out and placed DIMM slots (so it doesn't intrude on a big HSF), but the SATA connectors should of been right angled at edge of board and the IDE connector switched with the Floppy (most are used as CDROMs which are on the left side in a standard ATX placement), which itself should be eliminated altogether with advent of USB thumbstick drives (as well as a COM Port!!! Egads!). As other alluded to here, the MCP7A gets quite hot even if it is a 65nm part, so i took out the goop Asus used and placed on some Artic Silver AS7 on. For those that are wondering, yes my CPU (a Q9300) was lapped.
First and foremost, the AMI BIOS is annoyingly slow to boot, especially if you have a lot of SATA drives connected like me. Even if you disabled Express Gate and the bootup splash screen, it spends quite a few seconds querying the drives (unlike the G45 which is lightning quick). The Bios menus themselves aren't very detailed (i'm still confused how to underclock / overclock my CPU) and the choices very limited compared to my G45. I'll play with this later though once i get some stability into the system.
Second, half of my bootups appear to get stuck for whatever reason. It is really annoying and reminds me of the old days of the first Athlon 64 X2 boards from Asus / nVidia. I'm sure in time, this will be worked out via the BIOS but I spend half the time waiting to see if it boots or not and restarting again.
Third, the RAID configuration is a PITA to install with Vista 32. Unlike Intels ICH9/ICH10R, nVidia's RAID controller isn't included in Vista's core driver set thus requiring you to add it via Floppy (egads again!) or fortunately a USB thumbdrive. However, after Vista was installed, i ran through a few crashes during bootup. After yanking out my 5 Seagate 1.5TBs temporarily, things seemed to have calmed down with Vista letting me install SP1 and the appropriate drivers.
Next up....BD playback, undervolting, overclocking, vDroop measurements, RAID performance/configuration, and Speedfan configuration....