This is the stereotypical romantic drama which tries to use the successful mix from Speed between Bullock and Reeves. It doesn't really work.
The movie is quite flat and the plot is quite nonsensical. Of course, in a movie with time traveling you cannot think much about that part of the story or will fall apart. Not specifically, the fault of this one. But the behavior of the characters is really, really pointless in some parts.
Also, the parallel family struggles of both characters are quite pointless and irrelevant for the main story.
The main mistake, however, is the lack of spark that Bullock and Reeves did have in Speed. They are just numb.
The best part, the beautiful setting of the Lake House.