Hey there, welcome to the forums!
I don't have any prior experience, but I'm looking at the same kind of things as you. First up, I'll say that I put Monash Engineering down as my first preference. One of the perks of Monash engineering is that if you don't know which specialisation you want to do, you have a common first year, and you don't decide on specialisation until after trying out different types of engineering.
RMIT is a very good university for engineering, but you have to choose your area straight up, which was a problem for me. Also, I think the first year is in the City, but subsequent years are at the Bundoora campus, so that could be something to watch. Travel is always going to be something big to consider, make sure that you can easily get to the different unis or live on campus.
I don't know much about Swinbourne, but I don't believe that it is as well respected, having used to be just a Tech school, rather than a Uni. I guess that of the 3 it will be the easiest to get to from most places, being right close to PTV.
Hope this helped, feel free to message me any more questions.