Massachusetts is an attorney state as well and I have E&O. I've had E&O since the early 1990s when it was first made available to abstractors.   I am not an employee, so I'm not covered by any of my clients.  E&O is a real necessity - none of my clients will work with an abstractor who doesn't have it.  If I miss something on a title it's not their responsibility- it's mine because I provide them with the abstract of title.  

I use American Insurance Professionals in Arizona.  They do a great job, year after year.