I now have close to 20 LLCs It is a nightmare, expensive, complex, and an accounting disaster. there is a lot to be said for keeping it simple. 

I happen to own a small parcel  in a shopping complex that has great demographics and is always busy.  

It just adds another layer of complexity to the process, it will hurt part-time agents and drive many out of business, which is frankly not a bad thing.Buyer-side commission is now no longer set as a typically uniform percentage on MLS and fully negotiable. 

It reviews a number of different structures with  the advantages / issues of each;http://www.mondaq.com/canada/x/334102/Capital+Gains+Tax/Are+United+States+Limited+Liability+Limited+Partnerships+the+Holy+GrailAdding anther layer of complexity is; how much are you generating in profits?

I'm also wondering what type of properties people have been successful with (single family home, small condo projects, or large complexes).

I lived in 4 different apartment complexes during college, and this was my experience as well.

There are some very complex, fancy spreadsheets available for less than $10 that let you manage up to ten units.

Question though - why have you decided to create this multiple tiered structure and so much complexity? 

But they're really not that complex or expensive.

Its powerful, and can be as complex as you want it to be.