f2f,

You mean for-profit universities, not private universities. 

Most of the colleges and universities in the United States are private, such as Harvard, Stanford, Duke, etc.  Those that are not private are called state universities, such as Penn State, UCLA, UT, etc.  Whether they are private or public (state), they are all non-profit - meaning their main purpose of existence is research and education.  They do not, will not and can not make profit.  They run mostly on endowments and only 25% or even less of their budget are met by tuition and fees charged to the students.

For-profit universities are, in essence, businesses created to make money for their shareholders.  They make profit from the services they provide, i.e. the income they generate from their students.  The tuition, fees and other charges they collect from the students not only cover their total budget but also provide money (if profitable) to their shareholders.  Strayer University is one of these for-profit schools where lots of Nepalis attend.  University of Phoenix, Devry University, Kaplan University are some more examples.

Obviously, attending public or private non-profit universities is more traditional and prestigious, despite the fact that they may belong to the same accredition board as for-profit institutions.  But for-profit schools can be a viable alternative for those who do not wish to go through the rigor of traditional admission process.  These schools generally do not require standardized tests such as GRE or GMAT.  They are also comparatively lenient on the attendance factor, which obviously speaks volumes of the quality of education you get there, but for some this might be the particular attraction.  They also provide I-20s easily, an alternative that is beneficial to those international students who are at risk of being out-of-status.  Basically you pay, and you do pay, for what you get.  There is little or no scholarship, both monetarily and academically.

So the bottom line is, if your primary goal is intellectual achievement, then your most likely destination will be non-profit, traditional schools - whether public or private.  If you are looking to maintain your visa status and/or you have a fulltime occupation and education or training is more of a part-time endeavour, then for-profit schools are viable alternative.