I've been to Vallier a couple of times, both for brunch and dinner. I went for dinner last week and had grilled chicken with a maple reduction, asparagus, and mashed potatoes. The food is always consistently good, but not anything spectacular.
The prices are a little steep for what you're getting but that's pretty common in Old Town. It's a good place to go if the line is too long at Le Cartet, otherwise I would try somewhere else.