AI is a for-profit institution... meaning these programs are run as a business, not as a student-focused educational institution... take that into consideration as you are looking over their materials and talking to their recruiters...
I agree with jbyun04 that these schools are not known for stellar students or great portfolios. For many of these programs, the only requirement for admission is the ability to pay your tuition.
These schools have high placement rates because they are primarily teaching technical skills... while 94% of students may get jobs right out of school, the bigger question is are they succeeding in the industry over time?... In my experience many of these students "wash out" of the industry, stay in dead end jobs, or wind up continuing their education at another school after a few years.
Vegas is a tough market, as you have 3 for-profit schools competing there... Another option is UNLV, which has a NASAD accredited Fine arts program with a concentration in Graphic Design.
If you are looking for a more professional degree in GD, you will have to look a bit farther afield. There are several strong programs in LA, for example.