Skytrucker
I have used SITA for the past 10 years and overall they are very good. Back up is excellent, 24/7 and the guys on the help desk are all qualified FAA dispatchers or Ops bods. SITA airport data is also one of the best I have used and is approved/used by Boeing and Airbus themselves.
Have previously used Jepps and Air Data but overall prefer SITA.
Opsdog
All suppliers have their faults, but all I can say is that SITA have at the last count, over 230 airlines worldwide using the system, so it cant be all that bad. Yes the ARB was/is dodgy but I understand there is a new Nav Data base being Beta tested with a European airline which is showing good results and should be on line early next year. Amongst other enhancements, the system will alert the user if a notam closes an airway on an already filed or calculated CFP and then do a re-rte if required. "Which is nice".