I like that they are always willing & able/willing to take extra steps for us if needed or offered! They have been great in terms of communication as well - our projects manager has kept me up t date every step along way about everything from initial quote through first release (which was an iOS update).
We've also used them at least twice now when it came time adding new features / functionality after launch but before going out again publically via their site etc., which makes sense because some people will see bugs there sooner than others so wanted those issues fixed quicker rather then waiting till later down road once things were more widely known?