Good luck!
I agree with the other suggestions to review some of the old "what to do/what not to do" threads. It sounds like you're open minded about the groups, which is a good attitude. Formal recruitment is hectic, so feeling like you didn't click the first time through isn't necessarily a bad sign...you might go back through this year and fall in love with the women of the house!
Not sure what your campus is like, but since there are only 4 sororities I'm assuming maybe its a little more low-key, with possibly smaller houses. Remember this - if the average chapter size on your campus is not huge, the "personality" of a sorority can turn around quickly - sometimes it only takes one pledge class! Each of the chapters could have went through changes in the past year, and also each of them could have the potential for change through the upcoming pledge class. Definitely give them all a chance keeping that in mind.
And, although your campus may not
require them, it never
hurts to get rec letters!