I remember watching this when it first started. I found the premise entertaining and was somewhat jealous of the guys (3 guys at an all girls school, gotta love those odds). It set up an interesting love triangle early on between one of the main guys and a gorgeous upper-classman (which he wanted) and a friend of his (which wanted him). I didn't know which one I was pulling for.
The show featured some actors that would soon go on to bigger and better things: Milo Ventimiglia (Gilmore Girls; Heroes), Allison Mack (Smallville), and Chris Evans (Fantastic Four). It also proved to be decently funny but Fox quickly cancelled it with (at that time, I didn't pay too much attention to ratings and TV news) no known reason to me.
I think the show coud have managed to be entertaining for a while but didn't have much staying power in the long run. I would have enjoyed it for a few seasons maybe and then been ready for it to end. At least I still get to see some of these actors on better shows, though I wish I could have seen just a little more of "Opposite Sex" before it ended.