From my experience, the DAT RC is easier than the MCAT one, at least the Canadian one. I studied for the MCAT in 2012 and found that the questions had a lot of inferential questions and made you really analyze the passage. Also, the MCAT passage topics seemed really random at times (I remember a passage about different types of knots). The real DAT passages were more closely related health sciences. To study for my DAT RC, I used DAT Bootcamp and Crack the DAT. I did a practice test every 2nd day for the last 2.5 weeks and ended up with 21 on the real DAT. I'm sure it couldn't hurt to use the MCAT study material, but I just didn't want to risk it since this was a weak spot for me.