State Farm has been awesome for my portfolio as well as personal... They saved me alot of money from American Family. There were cheaper than everyone else that I tried and are a pleasure to do business with. I do not require renters insurance
I use Allstate for all of my personal and rental properties. My agent has been untouchable on my rental properties. Comparing apples to apples, Allstate has consistently been half of some of the other companies.
I do require my renters have renters insurance and my lease has their insurance cover their items during a loss to the property.