It is compatible with softimage. The video is rca and s-video. As with most systems in order to do video work you will need a raid. Medea is cheap and compatible. I believe the video I/O is uncompressed or compressed. It does have firewire but I do not think it can be used to capture video.
I bought mine from an sgi reseller. You should be able to get one for 2,000 to 3,000 with monitor. I paid almost 3,000 with 21" monitor.
If you are looking for a newer machine on the remanufactured sectioon of the sgi website they have the newer 230,330 and 530's from about $1,100. These are your standard issue pc, no special sgi graphics just nvidia cards.