Had to add my 2 cents here:
We had a Tektronix 740 for about a year. I was not impressed at all, very happy when we got ride of it (actually I think it’s in storage still). I found it slow and used up toner fairly quickly. Make sure you have all the correct settings when printing or else you can do serious damage to it. We had to replace the drum kit (I think it was that) twice because of that mistake(exspensive).
Presently we’re working with a HP Color LaserJet 8550N. It’s been a good workhorse so far (1.5 years). Granted this was an $8000 machine and I don’t think you would have that in your classroom budget. It’s been good with colour matching and very good on speed and consumables. The only complainant I have is with the HP drivers. They don’t actually use PostScript drivers, just emulated PostScript drivers, so that has caused a few problems. It’s also a beast, as big as a photocopier. But I like it better than the Tektronix…. that reminds me, I wanted to throw it off the top of our building…