I've tried a few places. There was one across from Vaughan Mills mall called 'La Taquizza', this one was alright...not the best of the lot. It was pricey for a burrito there.
Then there was one I tried near the Toronto Congress Center (Mississauga Area) I don't know the name of the venue but it's right beside the Harvey's there. They sell the 'BIG *** BURRITO' there, so far that one was pretty good. I'd actually recommend that one.
And I tried a place when I went to 'Taste of Danforth', I also don't remember the name of the venue but it's around danforth. Update: I THINK it's called 'The Burrito House'.
So depending on which area you're in you might want to try them out.
I haven't found the perfect burrito place for me that would keep me coming back yet. However when it comes to falafel, I've tried a TON of places and so far Me-va-me is THE BEST falafel place I've eaten at. As for Pho, I've tried many Pho restaurants. Best one was Pho 88 on Steeles and Warden.