I'm not sure how things work in Canada, but in my experience in the suburban Chicagoland area, the vast majority of midwives work in conjunction with OB practices. I believe in the state of Illinois, all Certified Nurse Midwives must work under the supervision of an OB. The few issues that did come up during my pregnancies were automatically handled by the OBs in my practice. A good midwife knows her or his limits and knows when to defer to the doctor. I never felt that I was getting sub-standard care from the midwives. If anything, I felt like I was getting better care because my midwives took more time to listen to me and my concerns.
With both of my children, I have gone with mixed practices that have both OBs and midwives. I am definitely more inclined to want to deliver with a midwife, but it is reassuring to be established with an OB in case of a complication. My DD was caught by a midwife and my son was caught by an OB from a completely different practice (since he delivered after only five minutes of pushing and was seconds away from being delivered by my labor and delivery nurse

). With my deliveries, 95% of the work was done by the labor and delivery nurses. The doctors and midwives (at least where I live) show up for a couple of minutes here and there and don't arrive until the very end. If you're concerned about complications, choosing a good hospital with a highly experienced staff is probably more important than the midwife vs OB issue.
I must say that my post-partum care with the midwife was about 100 times better than the post-partum care that I received from my OB. My midwife (and her partner in the practice) visited me several times in the 24 hours that I was at the hospital after delivery. My OB with my son blew into the hospital long enough to say that I could go home. Maybe this had more to do with personality than anything else, but you seem to hear this type of scenario over and over again.
Others have mentioned it, but keep an open mind towards natural childbirth. Both my children were delivered without the intervention of drugs/epidural and it was incredible. Did it hurt...of course, but it wasn't unbearable and it's not like you have to go through it everyday. I also feel that by not being numb and having more control over your body, in a lot of ways, you may have a much easier delivery. I felt GREAT afterwards. Honestly, I could have taken on the world after delivering. If you have any interest in this, I would highly suggest taking Bradley classes. Feel free to PM me if you have any questions about it.
Good luck, and congrats!