Citi Housing has nothing to do with Bahria Town. Its a separate housing authority run by Malik Riaz's son in law...
Prior to starting his own scheme, he was working in Bahria Town. There are issues and differences btw Mr.Malik Riaz and him... they are not on good terms. He is also using ditto copy desgins of monuments used in Bahria Town and trying to give impression that his scheme is a project of Bahria Town.
As for investment.. remember its not as proper and established company as Bahria Town. The property investment is like stock market.. you make many or loose many in blink of an eye!
Personally i'd recommend you Bahria Town Karachi for investment purposes.