If you could afford either, would you recommend Chateau Frontenac or Hotel Dominion for 3 nights in Quebec Ciy?

May as well go for The Frontenac .

I haven't stayed at either recently, but if you do a search for the properties on this forum you will probably come up with some good information. There have been several postings in the last few months on your general question.

Dominion, Dominion, Dominion!!! Absolutely!!

Part of the charm of Quebec City is that high-style Euro-flavour which Dominion has (and the Chateau definitively has not). AND they serve rillettes de canard with your breakfast.

You can always stroll through the Ch. Frontenac or have a meal there, if you really want to.

They are night and day, so it depends on what you want. Do you like traditional, overstated and big or modern, minimalist, and small?