We have a 1000i currently. I'd suggest looking at cost other than the machine. Our parts cabinet is worth probably more than a lot of people's cars. You'll definitely want to have parts on hand. I think I've seen drums on eBay for +/- $400, I think a toner bottle goes for 2-300. Fuser belts are 1500ish and I think in a year I've went through at least 4. I've went through 2 delevoper units. 3500ish a piece. The bigger the machine the bigger the cost. Also, the fiery isn't a cheap piece of equipment either. We had to it worked on once.
Now if if your looking to buy and then put on a click maintainence plan, that's a different story. We looked at doing that. One thing to note is your don't have the full satisfaction guarantee if it's a used unit for a refurbing place. That's risky considering if you use it a lot and image quality goes down, basically you have no leg to stand on. They can say "it's up to spec" or "we've done everything" and you don't have much of a recourse.