eng at uts really isnt that bad lol, id say it is one of their strengths. however, their biggest advantage is that it is standard to take a diploma of professional practice alongside the engineering degree, this allows u to get 12 months of work experience before graduating, which naturally is a large advatnage compared to the 3 months offered at other unis. however, taking the business degree removes this component, so you will also be getting 3 months of experience in the double degree. in this case i would say that unsw and uts are probably equal, though of course people will say that unsw's program is more intense and has more content and so on, which could be true due to the more compacted curriculum at unsw due to trimesters.
from what i know commerce is a less general degree than business, this means u would likely pick a specialisation and really drill down into that. conversely business is a bit more general and you wouldnt be as focused on a singular discipline, there is a bit more overlap (someone else probably knows more about this and can give better advice). the other thing is that it seems that uts' degree offers a major in management, but i cant see this as an option in unsw's degree.
both are probably good options, id say just pick whichever is more convenient to get to, and which curriculum you prefer, since one doesn't have the managerial major and one has trimesters.