Hey,
I wrote the Canadian DAT twice. The first time I took it, I took the Kaplan course in September, which ended just about a week before the DAT. I just found it really hard to keep up, since I was in 4th year, and thought my course material was more important, and so I decided that this would be my "take the DAT for 'fun'."
The second time i took it, I took the Kaplan course in the summer - I found this helpful, because it forced me to review a bit everyday (I'm a big procrastinator) and then just like the others, I did some intense reviewing about 3 weeks prior to the DAT.
Good luck!