Hi Skytrucker,
The company I work for uses SITA for our flight planning and flight watch.
My advice is TAKE AVOIDING ACTION!!!!. The ammount of problems we have had recently have driven us round the bend.
I think the main problem is the method of communication with their main system is antiquated and unreliable. Also, if we have to plan a route that is not pre loaded, we have to use a tool called the Automatic Route Builder. This is supposed to produce the best possible route but nine times out of ten it sends back total cr*p and routes that fail Eurocontrol.
As far as I'm concerned, it's more trouble than it's worth, but then I am sure that someone must find it OK.
Good luck