I've used both Dr. Morrison and Dr. Dallimore (from Port Perry/Brooklin vet services, 905-655-3337; and Uxbridge for Dr. Dallimore, 905-473-1320) and I would recommend either of them. I find them to be professional and knowledgable.
I especially like Dr. Dallimore's way of billing because he gives you a write up of services/findings in the invoice... this gives me a written record of the health of my horse!