I don't know how the tuitions compare, but as an employer in a design oriented firm in Southern California, my opinion is that SLO is the better school for those that want to practice architecture. SCI-Arc graduates tend to have better visualization skills, but are less capable when it comes to the design of buildings that looks like buildings. If your intention is to get your first professional degree at the grad level (which I would only suggest if you aren't 100% sure you want to be an architect), I would do your undergrad outside of architecture.

Just my opinion and there are of course a lot of variables involving individual students.

1. In addition to tuition cost, think about living expenses - living in DTLA is a lot more expensive than living in SLO.

2. As bass assassin noted, SLO has a better reputation for turning out technically proficient architects (although this is not 100% - a couple of the best technical architects I've worked with have been SCI-Arc grads); SCI-Arc and GSD have better reputations for getting you unpaid or low-paid internships with "starchitects", which I've been told is less fun than it sounds (not an experience I've had myself, although as a technical architect, I have to admit I'd love detailing a Gehry or Moss building once in my life).

S.L.O. all. day. long.

Look at the overall cost of attendance for SciArc like, rent, meals, mandatory computer purchases, and the like.  I'm quite certain it will be higher than SLO.   Also beware of what happens if you have a bad semester grade wise: your scholarship will go bye-bye.  Even the best students can get sidetracked by an unexpected injury, illness, or an unreasonable/difficult professor.

These two schools are soooo different in many ways. Here's a shameless plug, listen to our last episode where we discuss which type of undergraduate school is best. I went to SLO, and know plenty who went to sci-arc... so much of what is said in the show indirectly refers to both those schools. 

The main question is why you are going to undergrad school? TBH it's kind of silly to say that you know that you want to be an architect AND that you know what kind of architecture you want to do (and therefore attend a speciality school like sciarc). I tend to advocate for a more mixed education, especially if you are just graduating high school. You will learn so much from non-architecture courses that will shape you as a person AND your design work.

'I'm heavily leaning towards SCI-Arc right now because I want to graduate with a better design sense and I want to work for a higher level firm or pursue a masters degree if I want to take that path.' Given your intensity and dedication already, your design sense will be just as strong (if not stronger) if you attend SLO or any other top ranked school. 

Good luck and congrats!