For engineering, UNSW is best in the southern hemisphere, but that doesn't answer your question. Basically people who choose engineering would usually either pick unsw or anywhere else. Between MQ and UTS, there both good unis but UTS used to be good at engineering, what I mean by that is they used to be good but not sure about now. MQ isn't famous for its engineering course, only famous for law and arts and medicine, so people who usually pick engineering between MQ or UTS would usually pick based on the atmosphere of the uni and uni life. In my personal opinion I would pick UTS since its in the city and your close to everything in the city. MQ is in the northern western region of sydeny in a semi residential urban area. It is really up to you where you want to go. There both I'm guessing equal in engineering education but UTS has the reputation for a better engineering school (engineering is what got them famous) based on past rankings. I would recommend checking on uni ranks engineering school ranks website. if there equal, then pick based on the environment and where you prefer to study, in the city or in a urban-residential area.
Good luck and hope everything goes well