First of all congratulations at looking at your college education as a business transaction. You obviously have the right attitude and maturity for college. So, given that approach, you need to do a cost benefit analysis based on available data.
Here is how you should make your decision:
(1) First, confirm the exact difference in cost between the two schools so that you have a measurable baseline. I see that you have already done this in your post. However, you need to go a bit farther in your analysis and include travel, incidentals, total cost of room and board, etc.
(2) Next, NTKS17 above is on the right track. You need to find out if the opportunities at Cal Poly exceed those at SJSU enough to justify choosing it. For example, which school has the superior internships and co-ops? Do not forget the co-ops! Some of these are highly paid positions while you are at school that lead to real jobs after graduation. Cal Poly traditionally has lot's of them.
(3) Find out the stats with regards to employment rates and starting salaries for each school. If you can make $100,000 a year after Cal Poly and only $65,000 from SJSU then Cal Poly would be the better choice because it would take many years to catch up in salary even with the debt.
(4) Look deep into your heart and see if you have a real preference at the gut level. Do the analysis and then check with your heart.
The question is that even with the cost difference, is Cal Poly still worth choosing. It is not a straight calculation.