How do these compare to notes or syndications as far as risk and hassle and returns?

i find the service folks with families to be a bit more stable and return the homes in better shape than the single folks but that of course is not a universal there is always an exception to that. 

I own a single family with four girls renting it out.

If you are ever going to borrow money later it will likely be at worse terms than the three loans you outlined above.I would invest any money you were planning on using to pay these debts downs on opportunities that pay greater than 5.49% returns.

But my tax returns don't show much of a profit on my first year.  

If your returns are just outpacing inflation in this market because you're risk averse then flipping will not likely be for you.

If you are not looking to scale or you're worried about property management you can invest with a company like Rockwell Debt-free Properties that will return you 8%. 

In return for providing all of the "come up money", the partner would receive 25% ownership stake and, as I mentioned, be paid back with interest. 

The maximum return you can achieve through equity is 3.25% and 3.87% respectively.

@Dan StewartThe founder of Vanguard, John Bogle wrote a pretty good book called "The Little Book of Common Sense Investing: The Only Way to Gurantee Your Fair Share of Stock Market Returns"