As far as how it is viewed, I know typically as long as not all three degrees: undergrad, masters, and PhD are not from the same school, it is fine to do two at the same place. If a good program, practical, comfortable, and not a stronger interest to try some place else/another program, then it can be in your interest to stay. It's how much another program or school might interest you more and afford to relocate that might be a stronger pull. There's something to be said for being in a good place. Best wishes with your decision!!