I am overseeing the turnaround of a large apartment complex, 100+ units, where most of the units are vacant and in need of serious rehab.  

Isn't this part of the reason a lot investors like apartment complexes... minimizes risks?

I have over 30-40 homes/apartment complexes I purchased under $30K and placed Section 8 tenants in them.

Number two to market a rental in a condominium complex, if it's hard to get inside the complex a lot of times gives the person that is looking for the property a hard time to find it.We've had a lot of problems with condos because agents and other people cannot find the unit and cannot get inside the unit and some of these HOA's do not allow you to put for rent signs outside of the complex which reduces your ability greatlyAlso you have  no control on the HOA fees.

I am relatively new to real estate investing, and I am looking to invest in single and multi-family properties (and one day apartment complexes).  

If/when I have $1M, I would look at investing it into value-add or income producing multi-family apartment complexes or retail strip centers.

It has taught and (still is) teaching me about the complexities involved.

I also managed a 24 unit apartment complex while going to school.

The Stanley Mickelsen Safeguard Complex (SRMSC) is an Anti-Ballistic Missile complex which was developed to preserve the United States’ second strike capability against Soviet nuclear missile attacks.

What are some of the common expenses involved in buying a multi famialy complex?