Most of the time you'll be fine, but when something bad eventually happens (with enough exposure over time, you are virtually guaranteed to have something bad happen), the outcome is likely to be catastrophic. 

Quality homes in B or better areas, with guaranteed long-term tenants in place.

The quick good/bad of Section 8:- S8 tenants tend to be rougher on the property (but not always)- Paperwork/inspections/etc. can be burdensome and tough to navigate (especially initially)- People often think FMR rates are guarantee rental rates but that's not the case- Usually the rent isn't 100% subsidized and a lot of people don't realize this- S8 tenants tend to stay a lot longer than cash tenants- Obviously, the guaranteed rent portionOverall, I'm neutral on the program.

Quite possibly the single biggest misconception that gets investors into trouble. https://www.biggerpockets.com/forums/311/topics/1216224-advi...I'm not suggesting that buying at 700 to 75% ltv is a guarantee at anything. 

Since appreciation isn't a guarantee I don't ever bank on that when crunching numbers.

If the 10 year treasury is at 5% which is guaranteed, investors will want a risk premium for the mortgage backed security which here is a great article on it. 

Most new investors look to Section 8 for "guaranteed money" and think it's easy.

@Nina Ning this is going to seem over-simplistic but the price, location, and the start date of the property virtually guarantees that only students will want to rent the property."5 Bedroom/2 Bath Duplex only 3 blocks from _____bar and 7 blocks from _______football stadium available August 1st, 2021" = what a group of college friends is looking for. 

You can't count on a guaranteed annual increase in rent. 

You have no guarantee that the company's value will increase or decrease but you have every reason to believe that over time it will do well.