You cannot record HDMI from the PS3... the PS3 has something called "HDCP"; which is a new age copy protection (think DCSS or Macrovision). Because of this, if you plug the PS3 through HDMI on your computer, no video will show up. However, the BMI Pro also has a breakout cable for YPbPr, which can do up to 1080i, so that is a good solution. HDCP was officially cracked last week... it wont be long before HDCP strippers come out.
The BMIP has two built in recording formats: MJPEG and Uncompressed Raw. MJPEG is crap, and you will see a lot of compression artifacts; but because of it, the files are 1/20th the size and you dont need a raid-0 array to record. If you choose Uncompressed Raw, you're looking at 10GB per MINUTE at 720p. Most hard drives alone are not fast enough to write this; so you will need a raid-0 array of two drives or more to write it. If you're willing to spend money, you can get something called "Cineform NeoHD", which gives you access to the Cineform Intermediate recording format. Cineform is GODLIKE; the video looks just as good as the Uncompressed Raw, at 1/10th the size, so it eliminates the need for a raid-0 array.
Also, the internal BMIP can not record 480p, only the Shuttle can.