We have Old Republic and are pretty happy with them. They are usually pretty quick to send someone out to look at the problem, but sometimes they send kind of dodgy companies. Like, they sent an Heating and Cooling company to fix our constantly-running toilet, and in the process they BROKE it, couldn't fix it, and it took about a month to get another company sent out to get everything working again.
Other than that, they've been great. When our water heater flooded the basement last year, Old Republic got someone out first thing the next morning. We got a brand new water heater for $50! (The price per visit).