What other advantages and disadvantages do you have one over other, as far as managing the 4-plex vs. duplex.

I'm at a big of a disadvantage because I'm a late comer.

There are soo many better hosts out there than WIX and you will start with a disadvantage if you just go with WIX.

Are there any disadvantages to paying a decent amount towards the principle each month?

Advantages and disadvantages of investing in mobile home parks?

However, there are a few things that would be a disadvantage.

@Glenn Barlow Good question, the traditional blind pool fund has several disadvantages , people are reluctant to invest in someone without a strong track record if they cannot review each deal.

You have a disadvantage because, just by being licensed, you're open to being investigated by the RE commission in your state, and you have more legal requirements than a normal investor, and more leverage against you in court if you ever get sued. 

Is the main disadvantage that property values are more volatile (so you would get hit harder in a crisis)?

If you think you need a really big window unit for some reason, running a new circuit usually lets you use a 240 V window unit if you want.One disadvantage to a window unit, especially if it's on the first floor in a less-than-great neighborhood, is that it's relatively easy for the bad guys to push it into the house from the outside, and then climb in through the resulting hole.