Ask for references, and call them. Ask to see a job he has recently completed, to look at the kind of care he takes in plumbing the main lines inside your home, installing the controller in a neat manner, and how much damage was done to the lawn during installation.

Call a couple sprinkler supply houses in the area and ask for the names of who they reccommend.

Who took more time in presenting a bid and actual design plan, not just some scribbles on a piece of paper.

Did either one actually measure your house's pressure or flow?

A price difference of a few hundred dollars can cost you a lot of heartache in the future do to sloppy / hasty workmanship.

I don't install any rainbird. Hunter and Weathermatic. I like them due to ease of adjustment and features.