Check the police department's crime stats for neighborhoods you're interested in, and take a gander at the quality of nearby elementary, middle, and highschools.

we also saw an increase in vacancies and a significant drop in the quality of applicants on those same units during that time. 

Are there any suggestions on quality HOI companies?

Closed and added quality property to our portfolio Lessons learned?

I'm thinking of ways to speed the process up, like offering a gift card as a leasing bonus.

Do you typically see that the overall cost (time and money) is more efficient working with a quality wholesaler, or do you find that your return on investment is better for running your own acquisition marketing initiative?

Views are important  but not the be all for quality rentals.

Looking for contractor that is reliable and does good work, that is comfortable with using 'big box store' quality materials and working quickly.

@Felipe Mejia did that and was still able to scale at a reasonable speed. 

Quality PM's would realize it's a long term relationship.