He was unpleasantly surprised with the management/collection/vacancy/repairs challenges there were on them, which drastically cut down his returns, raised his stress level, etc, and he had a long difficult time finding an avenue to exit owning them.

Still with this being said towns have rules in place against expanding attic/3rd level spaces so even keeping property as legal duplex with luxury loft is not a given.   

Find someone who is doing what you want to do at a higher level than you and make them a part of your life. 

Consider factors like flight convenience, property management options, and your comfort level with the local market conditions.

I'm actually licensed myself.Regulations would mean a higher entry level, which means that all the bad apples will be weeded out and I'm all in for that!

Quote from @Steven Gesis:  Important takeaway is due diligence review, not only deal level but sponsor track record - yes, past performance is not indicative of future results, but at least it's a metric to review.   

As does most, I am deeply passionate about the level of service I provide to my investors and tenants. 

Now, I think each person has to evaluate their level of risk comfort because being highly leveraged can also create problems if there are significant market shifts.

Given that it's synced with my PMS to automatically send SMS messages to the booking guest when sound levels get above the quiet hours thresholds I've set, it's been terrific.I haven't had any issues with the smoke sensor, so far.

The cost to "evict" may actually be 1/20th since 'stuff' doesn't have tenant's rights the way a residential tenant does, but the entire other basked of 'stuff' to deal with seems like it might be closer to 1/2 or 75% of the 'normal' level of time/attention/etc that you as the landlord have to deal with.... but you're only getting 1/20th the income.Unless of course you are going to tie these to the 7 units themselves, and moving forward every time there is a vacancy, include the storage with the unit as a bundled pair, and increase the rent accordingly.