Yes, I have some Quintums, now working on geting some Cisco Call manager on line.
The Quintum is stable and very nice, as long as you stay away from the A200. That unit have some troubles and Quintum does not have control over the issues.
I only play with quintum so far. Now I am on the procces to integrate the Quintums with a Cisco call manager. Not much experience yet, but still works with Cisco Call manager on the first try.