I had heard the hype of Ashtons also. When my bro went to Quebec, I asked him to try a poutine and hot dog and tell me how it was. He said it was good, but nothing special* that you can't find at any street corner in Montreal.
I heard Maison du Spaghetti is awesome though, my bro said it has some of the best spaghetti sauce ever!
I moved to Quebec City four years ago, and I only ate at Ashton twice. Both times it was pretty ordinary, not very good even. And it's kind of expensive for what you get. People in Quebec City are proud about Ashton simply because there aren't any in Montreal, not because it's good. If there was a turd sandwich joint exclusively in Quebec city, people here would tell you it's the best place ever. People find their pride in trivial banalities. Some find it in a fast food joint.
You should try Chez Victor. It's pretty cheap (13-15$) and the burgers are awesome. My friends always want to go there when they visit me. Le Turf Pub has some good food too and a fun ambiance.