The Indigo2 is serving as a nice, relatively quiet system on which to muddle around with IRIX and fits nicely into a stack of other RISC *nix workstations. My O2 is definitely a step up in terms of CPU & GPU horsepower, but it's not as quiet and doesn't stack at all.
With its matching 19" monitor my Indy is on display along the back wall of my living room along with an O2 and a few few other computers. On a gloss-white table the colour stands out nicely.
I'm more likely to spend screen time with the O2 because it has Alias Designer on it. But, what I like most about my Indy is the colourful ad written by the 15-yr old who was tasked to sell it for his dad.