I like that they have developed very extensive functionality for all types of airlines in one solution which is great! They are always willing to help you out if needed too (which was rare but when it did happen we were happy).
We actually had an issue where our system went down at work during normal business hours so some functions stopped working - however this problem has since been fixed by their team within 2 days!! Great customer service! Not much other than just how good they've made things run smoothly and quickly. That's really about everything there really needs saying here because everyone who works in the office loves them as well - even though they're not from Germany ;).