So, the agent may earn a profit getting a selling commission, but the agent is also responsible for marketing and other fees.

It's human nature not to factor in their time, nor large episodic real estate expenses etc.almost forgot this table chart from Mary Callahan Erdoes , she is the head of JP morgan asset management which has hundreds of thousands of high net worth investors, They are quite stringent when comparing their own investor's returns to other Asset classes

You can also be hit with special levies or increases in the fees as well as the condo board changing rules regarding rentals.Three years ago when I was looking at a higher end condo vs a single family home, the comparables in terms of rent were a condo for about $240K with monthly fees of $250 (I think) vs a single family home for $270K. 

Also, make sure you're factoring in a discounted rental rate as well. 

I moved properties into an llc in palm beach county and there wasn't a fee.

Or can you already start making deals (and 50% profit) by just being a RENC member (fees range from $100-single, $150-couple...)? 

A lot of landlords think it's dumb to list with a realtor, but if you have a landlord specialist, they will do all of the work and the renter will pay the realtor fee.

But the potential upside of the more expensive building is massive, plus you get a higher overall ROI when you factor in all 4 wealth generators (cash flow, loan paydown, appreciation, depreciation).

I know my architect and civil eng will help on those deciding factors, but just wanted to see if anyone had any thoughts.

It's wise to take into account market research and any upgrades or additional benefits for the tenant.Determining when to raise the rent is influenced by various factors such as lease renewal dates, local market conditions, tenant satisfaction, and lease agreements.