As far as I am aware, both UNSW and UTS offer good programs, meaning that, from an educational perspective, you are likely to be satisfied with your learning experience at either university.
Essentially, you should pursue the degree that aligns with your study interests the closest. This would be better than studying a degree that you might not be interested in just so that you can study at a particular university. The prestige of a university (especially in a case where the two universities that you are contemplating offer good programs) should not be prioritised as this factor alone, that is, attending a more prestigious university, will not guarantee high employability.
The elements that increase your employability mainly include your academic performance (i.e. favourable university results) as well as any relevant work experience (and the resulting application and improvement of the skills that you learn) that you may gain through opportunities such as internships. Candidates who can demonstrate these qualities will be competitive when they apply for jobs, regardless of the university that they attended.
Alternatively, if you strongly believe that studying computer science at UNSW is the path that you should be taking, you can enrol in either UNSW's Bachelor of Information Systems or UTS's Bachelor of Computing Science and transfer to that program at a later point in time.
I think that one of the differences is that the study of information systems entails a focus on the business environment, which makes sense to me when I recall Information Processes and Technology, where students are introduced to information systems. There was definitely a business-related aspect to these.
Someone else may be able to provide further information in this regard.
I hope this helps!