The UC system does charges higher tuition than the CSU system – but the UC system is also wealthier and provides more financial aid. So the net cost is often not very different at low to middle income levels (at high income levels, UCs usually do cost more, because the financial aid gets phased out). Note also that Merced probably has low housing costs by California standards, which is significant in a state where a year of student housing can easily cost more than a year of tuition.
The US Dept of Education’s “College Scorecard” puts the “average annual cost” of UCM at $13,011. That compares favorably to CSUs like Cal Poly Pomona ($13,390) or Chico State ($13,365). Your mileage may vary, but it could be worth submitting an application to see what kind of aid you get.
In terms of cost, admissions difficulty, and use of semesters, UCM is arguably similar to the CSUs on your list (which is why I suggested it). On the other hand, this doesn’t necessarily mean that UCM has any compelling advantages over the CSUs. The primary advantages might be:
(1) UCM is still small by UC/CSU standards. Some people claim that the administration is more helpful and that the profs are more accessible than at other California state schools. I have no first-hand experience, but it wouldn’t surprise me if this is true.
(2) UCM is still growing, and appears to be keeping up with the intense demand for higher education in California. Many CSUs and UCs are plagued by impacted majors, oversubscribed classes, and housing shortages. UCM doesn’t seem to have these problems to the same degree, at least not yet.
(3) UCM carries the “University of California” brand name, which is one of the most recognized “brands” in higher education, both nationally and internationally. OK, “Merced” is not the most valuable part of the UC brand, but it seems likely that it will appreciate over the long run.
Do these points outweigh the location, in a pasture outside Merced? Maybe or maybe not, but if CSUCI is on your list, then UCM seems like it could work too.