Fels is my top choice! I applied on 17th January (deadline was extended because of MLK Day).
I have heard that the application volume has risen this year, more than the school anticipated.. so expect tougher competition (for the 30-35 spots in the full time program) and perhaps a delayed decision announcement...
Re interviews, I think an interview is mandatory for the executive applicants only,
From website: (http://www.fels.upenn.edu/admissions)
"Personal Interview - All executive applicants are required to meet with us in person. Interviews are not required for full-time applicants; however, full-time applicants may request an interview."