I interviewed at SUNY last year (and I am a first year there now). SuzQ120 and RC are correct -- during the actual interview there are 3 or 4 faculty/admissions committee members there, and you talk to them for about 1/2-hour to 45 minutes. It's "open file", so they know a lot about you, and will ask you specific questions about your academics or experience (why did you get a particular grade in "X" class? which did you prefer, your commercial or private shadowing experience, and why?... etc.). It's a little more uptight than the PCO interview I had where I just chatted with a faculty member about random stuff, but remember, they're not trying to scare you -- they just want to find out a little more about you.
There is a writing sample, but it's an easy one (I think mine was "do you prefer learning from lecture or from the book and why?"). The purpose of it is just to verify that you're the person who wrote your personal essay for your application, I suspect.
I'm really glad I chose SUNY -- the class size is great (small -- 72-ish students per class), and despite what RC says, I think the faculty are great. It's a challenging program, but I think because of it we're being well-prepared for the boards.
Good luck with your interview, and feel free to PM me with any other questions you have! 🙂