Like others have mentioned, Pho Tien Thanh has a hole-in-a-wall appearance with frenetic service and questionable sanitation. All these elements are usually a recipe for a good pho experience and this holds true here.
I ordered their Special Pho and found the broth to be clean tasting and flavorful without being overly oily. The noodles had a nice consistency without being too chewy. The meat was of good quality and I particularly liked the brisket. The portions were also pretty good. I do wish there was more rare beef and also more raw onions.
The fried spring rolls were nice and crispy, however a bit on the small side. Overall, solid pho, but i'm still not sure if I can call it "the best in Toronto" since i've had more flavorful broth elsewhere. However, it's a good sign that it wasn't overly salty and I wasn't too thirsty afterwards.