I decided to buy the property from my grandfather using a gift of equity, which allowed me to take over ownership without having to come up with the full down payment and pay for the tax lien and his closing costs.

Sherman does seem interesting though because of the lower cost and growth potential.  

Evicting them, even after purchase, could be a lengthy and costly legal process.

It costs me $1,500 to evict a tenant with it usually taking two-three months.

Refinancing has more nuances than it seems, and so do closing costs.

However, I'm unsure about the costs of maintaining the SL in Spain, especially cause I read in some forums that these costs can be pricey..Do you have any views on the above based on your experience?

I predict that the substantial home price cost savings and greater control they enable the buyer to have will make them grow in popularity.

So, we now find most areas where the cost of PM leaves but the general real estate passive investment ROI for the investor hiring property management.  

Do you understand the added complexity, work involved, and costs? 

This will cost you money on the back end.