No disadvantage to using your own buyer's agent, and as a first timer well, "you don't know, what you don't know".

Carl,HUD has many disadvantages: 1.

If I misread the linked article, my apologies.Unfortunately, as the links in the article indicate, there is research evidence aplenty that certain names bring disadvantage over others generally in the US--e.g. one finds more opportunity with a name like Ron than Jamal. 

The only thing that is disadvantage your not on other booking sites.

However, this puts me at a disadvantage compared to cash buyers, since I'm not as liquid.

Neither approach is without problems, both have advantages and disadvantages.

What are the disadvantages of refinancing other than higher mortgage and refinancing fees?

And do you think I would be at a big disadvantage for getting deals if I don't offer cash?

So they are the disadvantages also.  

In terms of your actual question about notes vs. real estate, again mileage will vary by all the factors above but my own opinion notes are designed to have more protections (i.e. they are debt) but have disadvantages as well such as that you get no appreciation, less tax benefits etc.