What would you say the biggest issue has been?

Apparently now those investments are less interesting to city hall. 

I used to help manage 30+ STRs in the city with a McSwain Management.

West Valley cities like Buckeye and Avondale, East Valley spots like Apache Junction and Mesa, or growing areas like Casa Grande and Maricopa are worth exploring.

Since I cant account for what their money cost,I have found that is the biggest flaw.

The biggest differences between residential and commercial:  Scalability, financing are very different, property taxes may be different, Insurance is definitely different. 

In cities like Chicago, parking is always in demand.

I do feel like Haverhill is much in the "path of progress" than comparable areas like Lowell and Lawrence, so it's a city on my radar for sure.

The biggest thing with this is if something major happens are you legally covered if the unit is illegally rented. 

.- Cities like Toronto will levy another tax (Vacant Home tax) equivalent to 1% of the current assessed value of the property if the property is not occupied (rented, owner-occupied, family occupied, all count as occupied)- Land Transfer Tax: while the Province of Ontario charges anywhere between 0.5 - 2% of Land Transfer Tax when your transaction closes, you should expect to pay this amount twice if the property is in the City of Toronto .