Mike,
No one will absolutely guarantee that you will see sharks, but I have gone three years in a row and have seen sharks everytime so far. Last year, there were times when you could see five Great Whites from the cage at one time (below and at a distance). However, there were a couple of times when two would approach the cage fairly close together. The last trip I took (last Oct.), we had sharks almost solid for three days. I don't remember having one dive rotation without at least one shark!! It is definitely and incredible trip.
Thanks for the compliment on the photos!
Christie