We have the Oce' 9300, and have been using it since R-14 (now on 2007.)
The Oce' drivers really suck and we had lots of issues with them. In addition, they made huge plot files that took forever to process. We switched back to the HP emulation we'd been using on our CadJet, and all that went away, plus the files are 1/2 the size or less.
The only major problem we have is this: Sometimes we have to embed raster files (tiffs usually) into our drawings, and when you do this the plotter hangs if you try to plot multiple copies of such a drawing. Rebooting the plotter fixes that if we forget, and as long as I send the files with images in single copy mode, it works ok. (We don't have a colater BTW, so perhaps it's related to that. I've never figured it out.)
Performance plotting PDF's has been spotty, and so has plotting 3rd party drawings containing some types of images. Fortunately we don't have to do much of that.
Other than these things the plotter has been very reliable. We did a drum and wire change at about 90,000 feet, and there's a little plastic cog I gotta lube once in a while or it squeeks, but that's about it.