I don't know why the whole "frat/fraternity" argument persists. In college, I was instructed to say "fraternity" and correct people who say "frat". I could give two @(#& about what you call them, really. Use either word and I know what you mean.
Some frat-haters seem to have an extraordinary amount of venom saved up for these organizations and their people. Maybe it's the exclusiveness, the snob behavior, the measuring-up process during rush, I don't know. That said, modern fraternities are mostly overrated. Buying friends? Err, maybe. It's not exactly expensive to belong: $45 pledge fee, $175 initiation fee, $250/semester social fees (of course, this was 1991-1996). But it seems that a lot of my so-called "friends" are just of the fair-weather variety. I've haven't heard a thing from a few since graduation...and that was 5 years ago. My primary motivation for joining was gaining access to the social scene, although fraternities are most helpful in this regard when you are an underaged freshman/sophomore. By the time I became legal, I had enough of the fraternity, the b!tchy sororities and all of the time demands. Also, pledging was brutal on my grades. I was forced to change majors and even consider leaving the university. On hindsight, that was pretty pathetic, but that's the danger of being an impressionable 18-year old.
I generally do not recommend freshmen to pledge a fraternity. While there's a chance it could be a great experience, it seems more often than not, the experience and its effects are negative over the long run. It depends on the individual and the house (and the social structure of the university in question). Frankly, I feel a little "ripped off" by the fraternity. It's a double-edged sword, however, because I have some (pleasurable) memories of those days that will stand the test of time. What makes it difficult is that I was never an independent, so I can't compare what it would have been like to be non-Greek my entire college career.