We've got a few 850s in our ICU which are used with Puritan Bennett 7200 ventilators. In general they work well, but some staff find them complex to set up, with all the temperature gradient and compensation stuff on them. The units have been reliable, but the water chambers (or "domes") give problems with the vents - mainly because the vent fails the self test if there is even the slightest leak - which the chambers seem rather prone to do.
They do the job well and work well, so if you can keep the staff training in step with the staff change-over, you should be OK.
