The one area we have had serious problems with is their Flt Planning dept, ie routeing and acceptance of flt plans. 75% of the time their route is rejected and as a consequence we have to try manual route changes etc etc.
Just more hassle when you least need it esp for a short notice flight etc. Despite constant pleading to get it right you end up talking to someone in the US middle of the night knowing little about obscure Eastern-block country you are trying to overfly!!
We have now binned the service and use another which is far superior and works 95% first time and costs roughly half.
Happy Chief Pilot!!