As you know, California is an expensive state to live in. Thus, everyone makes more than in places where it is cheaper to live. For example, some CSU (CA St. U) grads make $50k/yr, while a Montana State grad might make $35/yr. This doesn’t necessarily mean that the CSU is a better school, or that you are better off making more money. I would think that $50k in CA is about the same standard of living as $35k in MT. Thus, you should probably go to school where you want to live after college. The CA employers will look from grads from CSUs who are willing to put up with the high cost of living in CA, and the MT employers will look for grads from MT schools who want to live in MT.
Note that a MT grad that moves to CA for a job will make more than $35k, while a CSU grad that moves to MT will make less than $50k. Some employers will find a potential employee “better”, because they “come from far away”, but most employers will hire locally. So, your best bet would be to go to a school where you would like to get offered a job. If you want to work in CA, go to Cal Poly or another CSU.
I graduated with a MS in Mechanical Engineering from Cal Poly. I found many CA employers who were interested in hiring me after graduating from Cal Poly in both northern and southern California and was offered a salary much higher than those from other CSUs In contrast, I graduated from PA with a BS in Engineering, and most employers were from the local area. I didn’t see any from California.
I interviewed also with a Missouri employer but was uninterested when I found the job was in St. Louis. That employer told me they were going to stop interviewing at Cal Poly, because they could not find anyone willing to leave CA. Thus, I would say that Cal Poly has more of a regional reputation than a national one. My professors in PA certainly heard of Cal Poly, but my friends and relatives thought I got into “Cal Tech”.
Thus, if you get into Cal Poly for Mechanical Engineering, and you want to live in CA, then just go. You’ll make more on average than other CSU grads, and you will find employment in CA.
On the other hand, if you want to live in Texas, go to Texas A&M. if you want to live in Colorado, go to Colorado St at Fort Collins.