90k is a pretty good wage especially for somewhere like newcastle where you can get a lot more home for your money renting & buying compared to sydney.
Personally I didn't like newcastle but that was more to do with my inlaws lol. It depends on what you are used to. Its a city but didn't seem like it to me coming from bustling liverpool. Too little going on for us but if you are not from or want a big city with tons going on you may love it. Some great beaches and lovely national parks though, great place for kids to grow up.