What does "better" mean in your view? The reason I ask this is because 'better' can mean so many things e.g. university rankings (which are more geared towards postgrad), better social opportunities, better teaching (?), etc. Most undergraduate degrees need to teach certain things to maintain accreditation so if both CS courses are accredited then they will teach
similar things. Particularly in an applied discipline such as IT/CS, the 'extras' are worth a whole lot more than just content e.g. industry experience/projects/internships, networking, etc. so a university that can facilitate these is extremely important.
I'm waiting for RMIT to offer theirs.
Provided they offer you one? Is it confirmed that you're going to get one or are you just assuming here? I'd be going with Monash personally if they have already formally offered you a scholarship and course admission.
I have heard good things about both unis for IT/CS so you can't go wrong. My advice to you would be to deeply consider the travel requirements, map out potential travel routes and how long it would
genuinely take you to get to and from the university in question. Keep in mind that travel times are a rough estimate only and there are factors that can influence the times e.g. train delays, traffic (particularly if you're crossing over from one side of the CBD to the other) and more importantly, consider that this has to be maintained on a consistent basis over 3+ years for a Bachelor's degree. Weigh up whether it's worth it and go from there.