It would depend on whom you ask. People that did not pass the web interview, or were rejected outright might have the impression that it is hard to get in, while many other people who sailed through the phone interview and were accepted within a week will say something entirely different. Personally, I believe that the criteria to apply is not that difficult, obviously you must be enrolled in college before you apply, and you must be able to pass a criminal background check before you begin employment with the company. Those things considered, it then boils down to the telephone interview which everyone stresses about (myself included), but seems to consist of a routine pattern of questions (from what I gather from several posts regarding this). Finally, I would venture to say that Disney has a large pool of applicants, and will extend invitations based on what roles an individual is willing to consider, company needs and possible relevant experience in available roles. This is not to say that applicants need experience, many have none whatsoever in their offered roles.
Your chance is as good as anyone else, given the ability to meet the initial criteria. Oh, and you obviously must meet the Disney Look!
Getting a reply is another matter. I have seen people accepted within mere days, and others not finding out for 2-4 weeks. There is also the possibility that Disney will place you on a pending status. I have noticed that people waited for several weeks to find out whether they were going to be accepted or not. Some got in, some were very disappointed after waiting so long to not be accepted. There does not seem to be a clear path that one can predict as far as notification, but Disney's stance is that an individual should be notified within 3-4 weeks after the interview as to their acceptance/rejection or pending status.
I do not have any idea how many people are accepted per semester, or rejected for that matter. I would be interested to know myself, but I am not sure who has that info, and whether Disney will share it with you or not, should you inquire.
Good luck to you, and follow your dreams!