We had the opportunity to visit both of them. Here is my view:

Saravana Bhavan (Mississauga)

+ves - Place and food are ok. Plenty of parking since its in a mall. $8.75 for plate meals is a good deal. Service was good and food came within 10 minutes. Qty is good, could not finish everything.
-ves - A bit spicy. Could cut back on the white rice.

Bombay Bhel (Richmond Hill/Markham near hwy 7)
+ves - Veggie thali is good. Qty is more than we could handle. Big naan and little rice, that we liked. Two veggie curries and daal.

-ves - Service is horrible. Took abt 25 minutes for them to take the order. I had to complain to the guy (wearing chashma) in the bar. Again took another 25 minutes to get the food. We wanted a papri chat, mild one. But it was too spicy even for me. So had to abandon it (and paid for it). I was in no mood to argue as we were hungry and waiting. There were two other desi families, rest whites. Looked like the waiters were avoiding desis. Still to give the benefit of doubt, left 15% tip. For the food, I would visit again. If they can improve the service and not ignore the desis, they will do even better.