Applications, Profiles and groups are awesome, though there are plenty of room to improve.
Modifying the core files is easy as the code is not encrypted.
Support especially Mark in forum is helpful so are other jomsocial customers, already forming a great support base.
Applications are so easy to develop and Documentation on Appz development is good but more is always better
3 month period between releases. For a commericial product they should release atleast monthly updates and not ask the customers to wait for three months to get new version. Been waiting for 1.2