I'd give it 3.5 stars. Nice patio and decent food but not particularly memorable.
The location is certainly great to enjoy a lovely day. The patio is mostly enshrouded by trees and bushes though, which is a bit of a pity considering its river-side location, if only I could've seen more of the river!
The menu for lunch is small and tries to be seasonal, with a good selection of sandwiches, a few daily specials and some regular entrees.
I tried their wood-grilled salmon. Portion size was perfect, not overly filling. The salmon was grilled to perfection, attaining a nicely crisp crust, the shards of pickled fennel and crisp haricot vert went well with the fatty fish and the creamy maitake mushrooms were a tasty and meaty side. The potato cake was rather redundant.
Overall, I would say this place has good service, passable food and a nice patio.