I used inContact for 4 years at Henry Schein, H&R Block and CVS Caremark and I worked there for a year. I am not at Contactual for the past 3 months. I have tons of information I could share with you. I know details about each of these products.
My experience with cloud computing in a contact centre context have all been positive in but one situation: When your Internet connection is down, you are completly cut off from all your Data. So it is important to always have a technician ready to fix issues with the web connection unless you want to lose precious time and money. And seriously, which Internet provider never has experienced any downtime?