There is not the unknown of the water not turning on, the pipes bursting, the outside not being cared etc.

Taxes- $1,312Sewer and Water- (paid by tenant) $90/moTrash- $0Heat/Utilities- (paid by tenant) $130/moHOA- $0Cap Ex and Ops (my personal minimum is $150/roof/month)- I had planned on 10%. 

Water sits on the window sill and warps the wood. 

Water dispensers mean floods.  

On Sunday morning, we got a call from the neighbors saying that there was a lot of water coming out of our garage!

Build the system, step away, be a service missionary with my wife and kids (e.g. bring clean water systems to third-world villages, disaster relief, etc.)"

Purchase price: 270kCurrently rented for: 3500/monthExpenses: 600/month (taxes, insurance, utilities < water for one unit)Prop Mgt: 300/month Maintainance: 120/monthCapEx/Rainy day:  230/monthVacancy: 175/ month (5%)Debt service:  1090/ month (@5% interest)Total:  2500 (approx)Cash Flow:  1000/month (200 per door)Downpayment: 70k (25%)Cash on Cash: 17%What are the downsides of such a package against a multifamily unit?

Check with the public works department to find out if city sewer, water, gas and electric are available for a new built.

I don't know a lot about this stuff either but I'm currently working with another investor to buy one of his rentals with seller financing, pretty excited about it good luck, we too are planning on having a lake house right on the water. 

It is on the water with a pier and small community beach - that helps.