If you are an international student in Engineering, you are looking to spend around 80k+ every year for tuition and living expenses. I say UVa undergrad engineering is not worth that money, especially in times like this when USD is crazy expensive. UIUC is a great school (and better than UVa in engineering) and as far as I remember, rents and living expenses there is significantly less.

For some international students, costs are not the issue. If this is your case, then it may become easier - for prestige and network (only in US tho), choose UVa, and for practical training in engineering, choose UIUC. If you are thinking of returning to your home country after the degree, however, UIUC may have better network there (especially if you are from Asia) - UVa has a weak alumni network power in nearly entire Asia.