I am senior engineer and can tell you that the basic salary is very bad comparing to the other benefits which are so far so good.
are you moving to doha alone or with your family?
you can get a family house for 6500(unfurnished 2 bedrooms flat)
your monthly expenses is not less than 3000 qr if you have 2 kids and it depends on your life style.
good luck and try to negotiate the basic salary
please note that you will get your paid vacation and bonus and many other benefits based on your basic salary
qatar is a nice country to live in.