The freeholder will spend (a lot of) your money in an unpredictable and uncontrollable fashion
The land owner will knock your building down and stiff you
Small things:
Hard to Right to Manage / Acquire Freehold
Other residents might be tenants and / or complete dicks
Weird construction (might not actually be bad, just different)
Two big things that could happen:
The freeholder will spend (a lot of) your money in an unpredictable and uncontrollable fashion
The land owner will knock your building down and stiff you
Small things:
Hard to Right to Manage / Acquire Freehold
Other residents might be tenants and / or complete dicks
Weird construction (might not actually be bad, just different)