I’m going to chime in because my husband is a prof at SDSU. His perspective is that everything about going to school at SDSU is difficult – it’s difficult to get your classes, difficult to find parking during prime times (T&Th 10-2), difficult to get your lunch without waiting in a long line & difficult to graduate in 5 years. This last point is especially important, because if you are going to end up paying 5-6 years for SDSU (SDSU has a 74% grad rate for SIX years – they don’t report their 4 year rate, which is disconcerting, but according to the college board it’s 28%!!!). Meanwhile, LMU &SCU have rates in the 70%s for 4 year graduation. Cal Lutheran comes in at 56%.
http://media.collegeboard.com/digitalServices/pdf/professionals/four-year-graduation-rates-for-four-year-colleges.pdf
So, I think you need to consider 5 years min at SDSU vs 4 years private. Also – is her major impacted? If so, she may not get to study the major of her choice. This is typically not an issue for private schools.
Furthermore, the class size at LMU/SCU is much smaller than the large state schools. One thing to look at is whether the classes are taught by professors or lecturers or grad students. You can get through SDSU without many classes that require writing assignments, simply because a prof doesn’t have time to read 300 term papers per class. Meanwhile, at private schools, not many classes have more than 150 people – most classes have about 50 or fewer. You will get far more personalized instruction & get to know your professors. It is very rare when my husband gets to know any of his students (he teaches 2 500-seat lectures/semester). When he gets asked to write letters of rec, he often can’t do it because he doesn’t know the students personally. When he taught at USD (prior to going to SDSU), he had classes of 30 kids & he knew them all by name & where they were from, etc. The smaller class atmosphere leads to a much more integrated learning community, in my opinion.
Lastly, as to your other thought – grad schools → depending on the field, where you went to UG does matter to a certain extent. For example, SDSU has a poor track record of sending any kids to med school, yet at UCSD, it’s commonplace (SDSU does have an AMAZING nursing program, though). In my husband’s Ph.D. program (at a top 20 university), there were over 400 applicants for 7 spots & only ONE person came from a non-top tier university (& that person came from Michigan State – a pretty good school). The others were from Yale, Duke, Columbia, Boston U., USC & Cal). I’m not saying that you can’t get to a top grad school from a CSU (or lesser ranked private – like Cal Lutheran), but it may be a lot tougher. If you are a high achieving student at a top tier school (this includes the UCs), grad schools know you are intelligent & hard working. Meanwhile, at SDSU, my husband has to use a textbook with 8th grade reading level to teach an intro GE subject course (and gets asked questions like “what does ‘adolescence’ mean?”). While the top 5%-10% of his students are brilliant (those who stand out are typically from OOS or International), the fact is that most are mediocre & the bottom fourth doesn’t belong in college (not prepared or they party their way to an F). The quality of the students you are surrounding yourself with is another intangible.