jz27
Hey jz27,
I'm in pre-med right now and I did quite a few interviews last year for my med entrance so I'll add my 2 cents to Lixin's response. Medify and MedEntry both have interview packages but to be honest I never tried either of those out. I just basically had to research the companies out there and take other people's opinion to see which one seemed the best. What I did try out was the iCanMed interview package. I'm not sure if I'm allowed to compare prep companies here but iCanMed was pretty good as it had like a 2-day workshop which taught this really unique way to approach each question; then you can get one-on-one classes to apply that if you want etc. If I had to be completely honest, I had two panel interviews (and others were MMI) and for the first one, I prepared so much and used all my preparation advice. The second one was much later and I didn't bother preparing at all (and I mean, nothing). Believe it or not, but I thought I did way better in the second one. This made me believe somewhat of what @Lixin was saying above.
Look, TLDR, I think if you know if you aren't that great at public speaking and forming responses quickly etc. (which is totally okay), maybe the prep companies would help but if you are amazing at public speaking or you've done tons of debating etc., maybe you should just think about preparing on your own.
Hope this helps and let me know how it goes.